PM> Install-Package Spire.PDF

using Spire.Pdf;
    using Spire.Pdf.AutomaticFields;
    using Spire.Pdf.Graphics;
    using System.Drawing;
    
    
    namespace AddPageNumbers
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Load a PDF document
                PdfDocument pdf = new PdfDocument();
                pdf.LoadFromFile("Sample.pdf");
    
                //Create a true type font
                PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial", 10f, FontStyle.Regular), true);
    
                //Create a PdfPageNumberField instance
                PdfPageNumberField pageNumber = new PdfPageNumberField();
    
                //Create a PdfPageCountField instance
                PdfPageCountField pageCount = new PdfPageCountField();
    
                //Create a PdfCompositeField instance
                PdfCompositeField compositeField = new PdfCompositeField(font, PdfBrushes.Black, "Page {0} of {1}", pageNumber, pageCount);
                //Set the text alignment for the composite field
                compositeField.StringFormat = new PdfStringFormat(PdfTextAlignment.Left, PdfVerticalAlignment.Top);
    
                //Loop through the pages
                for(int i = 0; i < pdf.Pages.Count; i ++)
                {
                    //Draw composite filed on each page
                    compositeField.Draw(pdf.Pages[i].Canvas, pdf.Pages[i].Size.Width / 2 - 20, pdf.Pages[i].Size.Height - pdf.PageSettings.Margins.Bottom);
                }
    
                //Save the result document
                pdf.SaveToFile("AddPageNumbers.pdf");
            }
        }
    }

Imports Spire.Pdf
    Imports Spire.Pdf.AutomaticFields
    Imports Spire.Pdf.Graphics
    
    Namespace AddPageNumbers
        Friend Class Program
            Private Shared Sub Main(ByVal args As String())
                'Load a PDF document
                Dim pdf As PdfDocument = New PdfDocument()
                pdf.LoadFromFile("Sample.pdf")
    
                'Create a true type font
                Dim font As PdfTrueTypeFont = New PdfTrueTypeFont(New Font("Arial", 10F, FontStyle.Regular), True)
    
                'Create a PdfPageNumberField instance
                Dim pageNumber As PdfPageNumberField = New PdfPageNumberField()
    
                'Create a PdfPageCountField instance
                Dim pageCount As PdfPageCountField = New PdfPageCountField()
    
                'Create a PdfCompositeField instance
                Dim compositeField As PdfCompositeField = New PdfCompositeField(font, PdfBrushes.Black, "Page {0} of {1}", pageNumber, pageCount)
                'Set the text alignment for the composite field
                compositeField.StringFormat = New PdfStringFormat(PdfTextAlignment.Left, PdfVerticalAlignment.Top)
    
                'Loop through the pages
                For i As Integer = 0 To pdf.Pages.Count - 1
                    'Draw composite filed on each page
                    compositeField.Draw(pdf.Pages(i).Canvas, pdf.Pages(i).Size.Width / 2 - 20, pdf.Pages(i).Size.Height - pdf.PageSettings.Margins.Bottom)
                Next
    
                'Save the result document
                pdf.SaveToFile("AddPageNumbers.pdf")
            End Sub
        End Class
    End Namespace

PM> Install-Package Spire.PDF

using Spire.Pdf;
    
    namespace RemovePage
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument object
                PdfDocument document = new PdfDocument();
    
                //Load a sample PDF document
                document.LoadFromFile(@"E:\Files\input.pdf");
    
                //Remove the second page
                document.Pages.RemoveAt(1);
    
                //Save the result document
                document.SaveToFile("RemovePDFPage.pdf");
            }
        }
    }

Imports Spire.Pdf
    
    Namespace RemovePage
        Class Program
            Private Shared Sub Main(ByVal args As String())
    
                'Create a PdfDocument object
                Dim document As PdfDocument = New PdfDocument()
    
                'Load a sample PDF document
                document.LoadFromFile("E:\Files\input.pdf")
    
                'Remove the second page
                document.Pages.RemoveAt(1)
    
                'Save the result document
                document.SaveToFile("RemovePDFPage.pdf")
            End Sub
        End Class
    End Namespace

PM> Install-Package Spire.PDF

using Spire.Pdf;
    using Spire.Pdf.Graphics;
    using Spire.Pdf.Graphics.Layer;
    using System.Drawing;
    
    namespace AddLayersToPdf
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument instance and load a sample PDF file
                PdfDocument pdf = new PdfDocument();
                pdf.LoadFromFile(@"C:\Users\Administrator\Desktop\Sample.pdf");
    
                //Invoke AddLayerWatermark method to add a watermark layer
                AddLayerWatermark(pdf);
    
                //Invoke AddLayerHeader method to add a header layer
                AddLayerHeader(pdf);
    
                //Save to file
                pdf.SaveToFile("AddLayers.pdf");
                pdf.Close();
            }
    
            private static void AddLayerWatermark(PdfDocument doc)
            {
                //Create a layer named "Watermark"
                PdfLayer layer = doc.Layers.AddLayer("Watermark");
    
                //Create a font
                PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial", 48), true);
    
                //Specify the watermark text
                string watermarkText = "CONFIDENTIAL";
    
                //Get text size
                SizeF fontSize = font.MeasureString(watermarkText);
    
                //Calculate two offsets
                float offset1 = (float)(fontSize.Width * System.Math.Sqrt(2) / 4);
                float offset2 = (float)(fontSize.Height * System.Math.Sqrt(2) / 4);
    
                //Get page count
                int pageCount = doc.Pages.Count;
    
                //Declare two variables
                PdfPageBase page;
                PdfCanvas canvas;
    
                //Loop through the pages
                for (int i = 0; (i < pageCount); i++)
                {
                    page = doc.Pages[i];
    
                    //Create a canvas from layer
                    canvas = layer.CreateGraphics(page.Canvas);
                    canvas.TranslateTransform(page.Canvas.Size.Width / 2 - offset1 - offset2, page.Canvas.Size.Height / 2 + offset1 - offset2);
                    canvas.SetTransparency(0.4f);
                    canvas.RotateTransform(-45);
    
                    //Draw sting on the canvas of layer
                    canvas.DrawString(watermarkText, font, PdfBrushes.DarkBlue, 0, 0);
                }
            }
            private static void AddLayerHeader(PdfDocument doc)
            {
                // Create a layer named "Header"
                PdfLayer layer = doc.Layers.AddLayer("Header");
    
                //Get page size
                SizeF size = doc.Pages[0].Size;
    
                //Specify the initial values of X and y
                float x = 90;
                float y = 40;
    
                //Get page count
                int pageCount = doc.Pages.Count;
    
                //Declare two variables
                PdfPageBase page;
                PdfCanvas canvas;
    
                //Loop through the pages
                for (int i = 0; (i < pageCount); i++)
                {
                    //Draw an image on the layer
                    PdfImage pdfImage = PdfImage.FromFile(@"C:\Users\Administrator\Desktop\img.jpg");
                    float width = pdfImage.Width;
                    float height = pdfImage.Height;
                    page = doc.Pages[i];
                    canvas = layer.CreateGraphics(page.Canvas);
                    canvas.DrawImage(pdfImage, x, y, width, height);
    
                    //Draw a line on the layer
                    PdfPen pen = new PdfPen(PdfBrushes.DarkGray, 2);
                    canvas.DrawLine(pen, x, (y + (height + 5)), (size.Width - x), (y + (height + 2)));
                }
            }
        }
    } 

Imports Spire.Pdf
    Imports Spire.Pdf.Graphics
    Imports Spire.Pdf.Graphics.Layer
    Imports System.Drawing
    
    Namespace AddLayersToPdf
        Class Program
            Private Shared Sub Main(ByVal args() As String)
    
                'Create a PdfDocument instance and load a sample PDF file
                Dim pdf As PdfDocument = New PdfDocument
                pdf.LoadFromFile("C:\Users\Administrator\Desktop\Sample.pdf")
    
                'Invoke AddLayerWatermark method to add a watermark layer
                Program.AddLayerWatermark(pdf)
    
                'Invoke AddLayerHeader method to add a header layer
                Program.AddLayerHeader(pdf)
    
                'Save to file
                pdf.SaveToFile("AddLayers.pdf")
                pdf.Close()
            End Sub
    
            Private Shared Sub AddLayerWatermark(ByVal doc As PdfDocument)
    
                'Create a layer named "Watermark"
                Dim layer As PdfLayer = doc.Layers.AddLayer("Watermark")
    
                'Create a font
                Dim font As PdfTrueTypeFont = New PdfTrueTypeFont(New Font("Arial", 48), True)
    
                'Specify the watermark text
                Dim watermarkText As String = "CONFIDENTIAL"
    
                'Get text size
                Dim fontSize As SizeF = font.MeasureString(watermarkText)
    
                'Calculate two offsets
                Dim offset1 As Single = CSng((fontSize.Width * System.Math.Sqrt(2) / 4))
                Dim offset2 As Single = CSng((fontSize.Height * System.Math.Sqrt(2) / 4))
    
                'Get page count
                Dim pageCount As Integer = doc.Pages.Count
    
                'Declare two variables
                Dim page As PdfPageBase
                Dim canvas As PdfCanvas
    
                'Loop through the pages
                Dim i As Integer = 0
                While (i < pageCount)
                    page = doc.Pages(i)
    
                    'Create a canvas from layer
                    canvas = layer.CreateGraphics(page.Canvas)
                    canvas.TranslateTransform(page.Canvas.Size.Width / 2 - offset1 - offset2, page.Canvas.Size.Height / 2 + offset1 - offset2)
                    canvas.SetTransparency(0.4F)
                    canvas.RotateTransform(-45)
    
                    'Draw sting on the canvas of layer
                    canvas.DrawString(watermarkText, font, PdfBrushes.DarkBlue, 0, 0)
                    i = (i + 1)
                    i += 1
                End While
            End Sub
    
            Private Shared Sub AddLayerHeader(ByVal doc As PdfDocument)
    
                ' Create a layer named "Header"
                Dim layer As PdfLayer = doc.Layers.AddLayer("Header")
    
                'Get page size
                Dim size As SizeF = doc.Pages(0).Size
    
                'Specify the initial values of X and y
                Dim x As Single = 90
                Dim y As Single = 40
    
                'Get page count
                Dim pageCount As Integer = doc.Pages.Count
    
                'Declare two variables
                Dim page As PdfPageBase
                Dim canvas As PdfCanvas
    
                'Loop through the pages
                Dim i As Integer = 0
                While (i < pageCount)
    
                    'Draw an image on the layer
                    Dim pdfImage As PdfImage = PdfImage.FromFile("C:\Users\Administrator\Desktop\img.jpg")
                    Dim width As Single = pdfImage.Width
                    Dim height As Single = pdfImage.Height
                    page = doc.Pages(i)
                    canvas = layer.CreateGraphics(page.Canvas)
                    canvas.DrawImage(pdfImage, x, y, width, height)
    
                    'Draw a line on the layer
                    Dim pen As PdfPen = New PdfPen(PdfBrushes.DarkGray, 2)
                    canvas.DrawLine(pen, x, (y + (height + 5)), (size.Width - x), (y + (height + 2)))
                    i += 1
                End While
            End Sub
        End Class
    End Namespace

using Spire.Pdf;
    using Spire.Pdf.Graphics.Layer;
    
    namespace HideLayer
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument instance
                PdfDocument pdf = new PdfDocument();
    
                //Load a sample PDF document
                pdf.LoadFromFile("AddLayers.pdf");
    
                //Hide a specified layer by index
                pdf.Layers[0].Visibility = PdfVisibility.Off;
    
                //Hide a specified layer by name
                //pdf.Layers["Watermark"].Visibility = PdfVisibility.Off;
    
                //Save the result document
                pdf.SaveToFile("HideLayer.pdf");
            }
        }
    }

Imports Spire.Pdf
    Imports Spire.Pdf.Graphics.Layer
    
    Namespace HideLayer
        Class Program
            Private Shared Sub Main(ByVal args() As String)
    
                'Create a PdfDocument instance
                Dim pdf As PdfDocument = New PdfDocument
    
                'Load a sample PDF document
                pdf.LoadFromFile("AddLayers.pdf")
    
                'Hide a specified layer by index
                pdf.Layers(0).Visibility = PdfVisibility.Off
    
                'Hide a specified layer by name
                'pdf.Layers["Watermark"].Visibility = PdfVisibility.Off;
    
                'Save the result document
                pdf.SaveToFile("HideLayer.pdf")
            End Sub
        End Class
    End Namespace

using Spire.Pdf;
    
    namespace DeleteLayer
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument instance
                PdfDocument pdf = new PdfDocument();
    
                //Load a sample PDF document
                pdf.LoadFromFile("AddLayers.pdf");
    
                //Remove a layer by name
                pdf.Layers.RemoveLayer(("Watermark"));
    
                //Save the result document
                pdf.SaveToFile("DeleteLayer.pdf", FileFormat.PDF);
            }
        }
    }

Imports Spire.Pdf
    
    Namespace DeleteLayer
        Class Program
            Private Shared Sub Main(ByVal args() As String)
                'Create a PdfDocument instance
                Dim pdf As PdfDocument = New PdfDocument
    
                'Load a sample PDF document
                pdf.LoadFromFile("AddLayers.pdf")
    
                'Remove a layer by name
                pdf.Layers.RemoveLayer("Watermark")
    
                'Save the result document
                pdf.SaveToFile("DeleteLayer.pdf", FileFormat.PDF)
            End Sub
        End Class
    End Namespace

PM> Install-Package Spire.PDF

using Spire.Pdf;
    using Spire.Pdf.Graphics;
    using System.Drawing;
    
    namespace CreatePdfDocument
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument object
                PdfDocument doc = new PdfDocument();
    
                //Add a page
                PdfPageBase page = doc.Pages.Add(PdfPageSize.A4, new PdfMargins(35f));
    
                //Specify heading text
                String titleText = "What is MySQL";
    
                //Create solid brushes
                PdfSolidBrush titleBrush = new PdfSolidBrush(new PdfRGBColor(Color.Blue));
                PdfSolidBrush paraBrush = new PdfSolidBrush(new PdfRGBColor(Color.Black));
    
                //Create true type fonts
                PdfTrueTypeFont titleFont = new PdfTrueTypeFont(new Font("Times New Roman", 18f, FontStyle.Bold),true);
                PdfTrueTypeFont paraFont = new PdfTrueTypeFont(new Font("Times New Roman", 12f, FontStyle.Regular), true);
    
                //Set the text alignment via PdfStringFormat class
                PdfStringFormat format = new PdfStringFormat();
                format.Alignment = PdfTextAlignment.Center;
    
                //Draw heading on the center of the page
                page.Canvas.DrawString(titleText, titleFont, titleBrush, page.Canvas.ClientSize.Width / 2, 20, format);
    
                //Get paragraph content from a .txt file
                string paraText = File.ReadAllText("C:\\Users\\Administrator\\Desktop\\content.txt");
    
                //Create a PdfTextWidget object to hold the paragrah content
                PdfTextWidget widget = new PdfTextWidget(paraText, paraFont, paraBrush);
    
                //Create a rectangle where the paragraph content will be placed
                RectangleF rect = new RectangleF(0, 50, page.Canvas.ClientSize.Width, page.Canvas.ClientSize.Height);
    
                //Set the PdfLayoutType to Paginate to make the content paginated automatically
                PdfTextLayout layout = new PdfTextLayout();
                layout.Layout = PdfLayoutType.Paginate;
    
                //Draw the widget on the page
                widget.Draw(page, rect, layout);
    
                //Save to file
                doc.SaveToFile("CreatePdfDocument.pdf");
                doc.Dispose();
            }
        }
    }

Imports Spire.Pdf
    Imports Spire.Pdf.Graphics
    Imports System.Drawing
    
    Namespace CreatePdfDocument
        Class Program
            Shared  Sub Main(ByVal args() As String)
                'Create a PdfDocument object
                Dim doc As PdfDocument =  New PdfDocument()
    
                'Add a page
                Dim page As PdfPageBase =  doc.Pages.Add(PdfPageSize.A4,New PdfMargins(35f))
    
                'Specify heading text
                Dim titleText As String =  "What is MySQL"
    
                'Create solid brushes
                Dim titleBrush As PdfSolidBrush =  New PdfSolidBrush(New PdfRGBColor(Color.Blue))
                Dim paraBrush As PdfSolidBrush =  New PdfSolidBrush(New PdfRGBColor(Color.Black))
    
                'Create true type fonts
                Dim titleFont As PdfTrueTypeFont =  New PdfTrueTypeFont(New Font("Times New Roman",18f,FontStyle.Bold),True)
                Dim paraFont As PdfTrueTypeFont =  New PdfTrueTypeFont(New Font("Times New Roman",12f,FontStyle.Regular),True)
    
                'Set the text alignment via PdfStringFormat class
                Dim format As PdfStringFormat =  New PdfStringFormat()
                format.Alignment = PdfTextAlignment.Center
    
                'Draw heading on the center of the page
                page.Canvas.DrawString(titleText, titleFont, titleBrush, page.Canvas.ClientSize.Width / 2, 20, format)
    
                'Get paragraph content from a .txt file
                Dim paraText As String =  File.ReadAllText("C:\\Users\\Administrator\\Desktop\\content.txt")
    
                'Create a PdfTextWidget object to hold the paragrah content
                Dim widget As PdfTextWidget =  New PdfTextWidget(paraText,paraFont,paraBrush)
    
                'Create a rectangle where the paragraph content will be placed
                Dim rect As RectangleF =  New RectangleF(0,50,page.Canvas.ClientSize.Width,page.Canvas.ClientSize.Height)
    
                'Set the PdfLayoutType to Paginate to make the content paginated automatically
                Dim layout As PdfTextLayout =  New PdfTextLayout()
                lay.Layout = PdfLayoutType.Paginate
    
                'Draw the widget on the page
                widget.Draw(page, rect, layout)
    
                'Save to file
                doc.SaveToFile("CreatePdfDocument.pdf")
                doc.Dispose()
            End Sub
        End Class
    End Namespace

PM> Install-Package Spire.PDF

using System;
    using Spire.Pdf;
    
    namespace SplitPDFIntoIndividualPages
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Specify the input file path
                String inputFile = "C:\\Users\\Administrator\\Desktop\\Terms of Service.pdf";
    
                //Specify the output directory
                String outputDirectory = "C:\\Users\\Administrator\\Desktop\\Output\\";
    
                //Create a PdfDocument object
                PdfDocument doc = new PdfDocument();
    
                //Load a PDF file
                doc.LoadFromFile(inputFile);
    
                //Split the PDF to one-page PDFs
                doc.Split(outputDirectory + "output-{0}.pdf", 1);
            }
        }
    }

Imports System
    Imports Spire.Pdf
    
    Namespace SplitPDFIntoIndividualPages
        Class Program
            Shared  Sub Main(ByVal args() As String)
                'Specify the path of the input file
                Dim inputFile As String =  "C:\\Users\\Administrator\\Desktop\\Terms of Service.pdf"
    
                'Specify the output directory
                Dim outputDirectory As String =  "C:\\Users\\Administrator\\Desktop\\Output\\"
    
                'Create a PdfDocument object
                Dim doc As PdfDocument =  New PdfDocument()
    
                'Load a PDF file
                doc.LoadFromFile(inputFile)
    
                'Split the PDF to one-page PDFs
                doc.Split(outputDirectory + "output-{0}.pdf", 1)
            End Sub
        End Class
    End Namespace

using Spire.Pdf;
    using System;
    
    namespace SplitPdfByPageRanges
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Specify the input file path
                String inputFile = "C:\\Users\\Administrator\\Desktop\\Terms of Service.pdf";
    
                //Specify the output directory
                String outputDirectory = "C:\\Users\\Administrator\\Desktop\\Output\\";
    
                //Load the source PDF file while initialing the PdfDocument object
                PdfDocument sourceDoc = new PdfDocument(inputFile);
    
                //Create two additional PdfDocument objects
                PdfDocument newDoc_1 = new PdfDocument();
                PdfDocument newDoc_2 = new PdfDocument();
    
                //Insert the first page of source file to the first document
                newDoc_1.InsertPage(sourceDoc, 0);
    
                //Insert the rest pages of source file to the second document
                newDoc_2.InsertPageRange(sourceDoc, 1, sourceDoc.Pages.Count - 1);
    
                //Save the two documents as PDF files
                newDoc_1.SaveToFile(outputDirectory + "output-1.pdf");
                newDoc_2.SaveToFile(outputDirectory + "output-2.pdf");
            }
        }
    }

Imports Spire.Pdf
    Imports System
    
    Namespace SplitPdfByPageRanges
        Class Program
            Shared  Sub Main(ByVal args() As String)
                'Specify the input file path
                Dim inputFile As String =  "C:\\Users\\Administrator\\Desktop\\Terms of Service.pdf"
    
                'Specify the output directory
                Dim outputDirectory As String =  "C:\\Users\\Administrator\\Desktop\\Output\\"
    
                'Load the source PDF file while initialing the PdfDocument object
                Dim sourceDoc As PdfDocument =  New PdfDocument(inputFile)
    
                'Create two additional PdfDocument objects
                Dim NewDoc_1 As PdfDocument =  New PdfDocument()
                Dim NewDoc_2 As PdfDocument =  New PdfDocument()
    
                'Insert the first page of source file to the first document
                NewDoc_1.InsertPage(sourceDoc, 0)
    
                'Insert the rest pages of source file to the second document
                NewDoc_2.InsertPageRange(sourceDoc, 1, sourceDoc.Pages.Count - 1)
    
                'Save the two documents as PDF files
                NewDoc_1.SaveToFile(outputDirectory + "output-1.pdf")
                NewDoc_2.SaveToFile(outputDirectory + "output-2.pdf")
            End Sub
        End Class
    End Namespace

PM> Install-Package Spire.PDF

using Spire.Pdf;
    using Spire.Pdf.Security;
    
    namespace EncryptPDF
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument object
                PdfDocument pdf = new PdfDocument();
    
                //Load a sample PDF file
                pdf.LoadFromFile(@"E:\Files\sample.pdf");
    
                //Encrypt the PDF file with password
                pdf.Security.Encrypt("open", "permission", PdfPermissionsFlags.Print | PdfPermissionsFlags.CopyContent, PdfEncryptionKeySize.Key128Bit);
    
                //Save the result file
                pdf.SaveToFile("Encrypt.pdf", FileFormat.PDF);
            }
        }
    }

Imports Spire.Pdf
    Imports Spire.Pdf.Security
    
    Namespace EncryptPDF
        Class Program
            Private Shared Sub Main(ByVal args As String())
    
                'Create a PdfDocument object
                Dim pdf As PdfDocument = New PdfDocument()
    
                'Load a sample PDF file
                pdf.LoadFromFile("E:\Files\sample.pdf")
    
                'Encrypt the PDF file with password
                pdf.Security.Encrypt("open", "permission", PdfPermissionsFlags.Print Or PdfPermissionsFlags.CopyContent, PdfEncryptionKeySize.Key128Bit)
    
                'Save the result file
                pdf.SaveToFile("Encrypt.pdf", FileFormat.PDF)
            End Sub
        End Class
    End Namespace

using Spire.Pdf;
    using Spire.Pdf.Security;
    
    namespace DecryptPDF
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument object
                PdfDocument pdf = new PdfDocument();
    
                //Load the encrypted PDF file with password
                pdf.LoadFromFile("Encrypt.pdf", "open");
    
                //Set the password as empty to decrypt PDF
                pdf.Security.Encrypt(string.Empty, string.Empty, PdfPermissionsFlags.Default, PdfEncryptionKeySize.Key128Bit, "permission");
    
                //Save the result file
                pdf.SaveToFile("Decrypt.pdf", FileFormat.PDF);
            }
        }
    } 

Imports Spire.Pdf
    Imports Spire.Pdf.Security
    
    Namespace DecryptPDF
        Class Program
            Private Shared Sub Main(ByVal args As String())
    
                'Create a PdfDocument object
                Dim pdf As PdfDocument = New PdfDocument()
    
                'Load the encrypted PDF file with password
                pdf.LoadFromFile("Encrypt.pdf", "open")
    
                'Set the password as empty to decrypt PDF
                pdf.Security.Encrypt(String.Empty, String.Empty, PdfPermissionsFlags.[Default], PdfEncryptionKeySize.Key128Bit, "permission")
    
                'Save the result file
                pdf.SaveToFile("Decrypt.pdf", FileFormat.PDF)
            End Sub
        End Class
    End Namespace

PM> Install-Package Spire.PDF

using Spire.Pdf;
    using Spire.Pdf.Security;
    using System;
    using System.Drawing;
    using Spire.Pdf.Graphics;
    
    namespace AddTextSignature
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument object
                PdfDocument doc = new PdfDocument();
    
                //Load a sample PDF file
                doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf");
    
                //Load the certificate
                PdfCertificate cert = new PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx", "e-iceblue");
    
                //Create a PdfSignature object and specify its position and size
                PdfSignature signature = new PdfSignature(doc, doc.Pages[doc.Pages.Count-1], cert, "MySignature");
                RectangleF rectangleF = new RectangleF(doc.Pages[0].ActualSize.Width - 340, 150, 290, 100);
                signature.Bounds = rectangleF;
                signature.Certificated = true;
    
                //Set the graphics mode to sign detail
                signature.GraphicsMode = GraphicMode.SignDetail;
    
                //Set the signature content
                signature.NameLabel = "Signer:";
                signature.Name = "Gary";
                signature.ContactInfoLabel = "Phone:";
                signature.ContactInfo = "0123456";
                signature.DateLabel = "Date:";
                signature.Date = DateTime.Now;
                signature.LocationInfoLabel = "Location:";
                signature.LocationInfo = "USA";
                signature.ReasonLabel = "Reason:";
                signature.Reason = "I am the author";
                signature.DistinguishedNameLabel = "DN:";
                signature.DistinguishedName = signature.Certificate.IssuerName.Name;
    
                //Set the signature font
                signature.SignDetailsFont = new PdfTrueTypeFont(new Font("Arial Unicode MS",12f,FontStyle.Regular));
    
                //Set the document permission to forbid changes but allow form fill
                signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill;
    
                //Save to file
                doc.SaveToFile("TextSignature.pdf");
                doc.Close();
            }
        }
    }

Imports Spire.Pdf
    Imports Spire.Pdf.Security
    Imports System
    Imports System.Drawing
    Imports Spire.Pdf.Graphics
    
    Namespace AddTextSignature
        Class Program
            Shared  Sub Main(ByVal args() As String)
                'Create a PdfDocument object
                Dim doc As PdfDocument =  New PdfDocument()
    
                'Load a sample PDF file
                doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf")
    
                'Load the certificate
                Dim cert As PdfCertificate =  New PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx","e-iceblue")
    
                'Create a PdfSignature object and specify its position and size
                Dim signature As PdfSignature =  New PdfSignature(doc,doc.Pages(doc.Pages.Count-1),cert,"MySignature")
                Dim rectangleF As RectangleF =  New RectangleF(doc.Pages(0).ActualSize.Width - 340,150,290,100)
                signature.Bounds = rectangleF
                signature.Certificated = True
    
                'Set the graphics mode to sign detail
                signature.GraphicsMode = GraphicMode.SignDetail
    
                'Set the signature content
                signature.NameLabel = "Signer:"
                signature.Name = "Gary"
                signature.ContactInfoLabel = "Phone:"
                signature.ContactInfo = "0123456"
                signature.DateLabel = "Date:"
                signature.Date = DateTime.Now
                signature.LocationInfoLabel = "Location:"
                signature.LocationInfo = "USA"
                signature.ReasonLabel = "Reason:"
                signature.Reason = "I am the author"
                signature.DistinguishedNameLabel = "DN:"
                signature.DistinguishedName = signature.Certificate.IssuerName.Name
    
                'Set the signature font
                signature.SignDetailsFont = New PdfTrueTypeFont(New Font("Arial Unicode MS",12f,FontStyle.Regular))
    
                'Set the document permission to forbid changes but allow form fill
                signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill
    
                'Save to file
                doc.SaveToFile("TextSignature.pdf")
                doc.Close()
            End Sub
        End Class
    End Namespace

using Spire.Pdf;
    using Spire.Pdf.Graphics;
    using Spire.Pdf.Security;
    using System.Drawing;
    
    namespace AddImageSignature
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument object
                PdfDocument doc = new PdfDocument();
    
                //Load a sample PDF file
                doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf");
    
                //Load the certificate
                PdfCertificate cert = new PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx", "e-iceblue");
    
                //Create a PdfSignature object and specify its position and size
                PdfSignature signature = new PdfSignature(doc, doc.Pages[doc.Pages.Count - 1], cert, "MySignature");
                RectangleF rectangleF = new RectangleF(doc.Pages[0].ActualSize.Width - 200, 150, 130, 130);
                signature.Bounds = rectangleF;
                signature.Certificated = true;
    
                //Set the graphics mode to image only
                signature.GraphicsMode = GraphicMode.SignImageOnly;
    
                //Set the sign image source
                signature.SignImageSource = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\verified.png");
    
                //Set the signature font
                signature.SignDetailsFont = new PdfTrueTypeFont(new Font("Arial Unicode MS", 12f, FontStyle.Regular));
    
                //Set the document permission to forbid changes but allow form fill
                signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill;
    
                //Save to file
                doc.SaveToFile("ImageSignature.pdf");
                doc.Close();
            }
        }
    }

Imports Spire.Pdf
    Imports Spire.Pdf.Graphics
    Imports Spire.Pdf.Security
    Imports System.Drawing
    
    Namespace AddImageSignature
        Class Program
            Shared  Sub Main(ByVal args() As String)
                'Create a PdfDocument object
                Dim doc As PdfDocument =  New PdfDocument()
    
                'Load a sample PDF file
                doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf")
    
                'Load the certificate
                Dim cert As PdfCertificate =  New PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx","e-iceblue")
    
                'Create a PdfSignature object and specify its position and size
                Dim signature As PdfSignature =  New PdfSignature(doc,doc.Pages(doc.Pages.Count - 1),cert,"MySignature")
                Dim rectangleF As RectangleF =  New RectangleF(doc.Pages(0).ActualSize.Width - 200,150,130,130)
                signature.Bounds = rectangleF
                signature.Certificated = True
    
                'Set the graphics mode to image only
                signature.GraphicsMode = GraphicMode.SignImageOnly
    
                'Set the sign image source
                signature.SignImageSource = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\verified.png")
    
                'Set the signature font
                signature.SignDetailsFont = New PdfTrueTypeFont(New Font("Arial Unicode MS", 12f, FontStyle.Regular))
    
                'Set the document permission to forbid changes but allow form fill
                signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill
    
                'Save to file
                doc.SaveToFile("ImageSignature.pdf")
                doc.Close()
            End Sub
        End Class
    End Namespace

using Spire.Pdf;
    using Spire.Pdf.Security;
    using System;
    using System.Drawing;
    using Spire.Pdf.Graphics;
    
    namespace AddTextAndImageSignature
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument object
                PdfDocument doc = new PdfDocument();
    
                //Load a sample PDF file
                doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf");
    
                //Load the certificate
                PdfCertificate cert = new PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx", "e-iceblue");
    
                //Create a PdfSignature object and specify its position and size
                PdfSignature signature = new PdfSignature(doc, doc.Pages[doc.Pages.Count - 1], cert, "MySignature");
                RectangleF rectangleF = new RectangleF(doc.Pages[0].ActualSize.Width - 320, 150, 260, 110);
                signature.Bounds = rectangleF;
                signature.Certificated = true;
    
                //Set the graphics mode to image and sign detail
                signature.GraphicsMode = GraphicMode.SignImageAndSignDetail;
    
                //Set the signature content
                signature.NameLabel = "Signer:";
                signature.Name = "Gary";
                signature.ContactInfoLabel = "Phone:";
                signature.ContactInfo = "0123456";
                signature.DateLabel = "Date:";
                signature.Date = DateTime.Now;
                signature.LocationInfoLabel = "Location:";
                signature.LocationInfo = "USA";
                signature.ReasonLabel = "Reason:";
                signature.Reason = "I am the author";
                signature.DistinguishedNameLabel = "DN:";
                signature.DistinguishedName = signature.Certificate.IssuerName.Name;
    
                //Set the signature image source
                signature.SignImageSource = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\handSignature.png");
    
                //Set the signature font
                signature.SignDetailsFont = new PdfTrueTypeFont(new Font("Arial Unicode MS", 12f, FontStyle.Regular));
    
                //Set the document permission to forbid changes but allow form fill
                signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill;
    
                //Save to file
                doc.SaveToFile("TextAndImageSignature.pdf");
                doc.Close();
            }
        }
    }

Imports Spire.Pdf
    Imports Spire.Pdf.Security
    Imports System
    Imports System.Drawing
    Imports Spire.Pdf.Graphics
    
    Namespace AddTextAndImageSignature
        Class Program
            Shared  Sub Main(ByVal args() As String)
                'Create a PdfDocument object
                Dim doc As PdfDocument =  New PdfDocument()
    
                'Load a sample PDF file
                doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\sample.pdf")
    
                'Load the certificate
                Dim cert As PdfCertificate =  New PdfCertificate("C:\\Users\\Administrator\\Desktop\\MyCertificate.pfx","e-iceblue")
    
                'Create a PdfSignature object and specify its position and size
                Dim signature As PdfSignature =  New PdfSignature(doc,doc.Pages(doc.Pages.Count - 1),cert,"MySignature")
                Dim rectangleF As RectangleF =  New RectangleF(doc.Pages(0).ActualSize.Width - 320,150,260,110)
                signature.Bounds = rectangleF
                signature.Certificated = True
    
                'Set the graphics mode to image and sign detail
                signature.GraphicsMode = GraphicMode.SignImageAndSignDetail
    
                'Set the signature content
                signature.NameLabel = "Signer:"
                signature.Name = "Gary"
                signature.ContactInfoLabel = "Phone:"
                signature.ContactInfo = "0123456"
                signature.DateLabel = "Date:"
                signature.Date = DateTime.Now
                signature.LocationInfoLabel = "Location:"
                signature.LocationInfo = "USA"
                signature.ReasonLabel = "Reason:"
                signature.Reason = "I am the author"
                signature.DistinguishedNameLabel = "DN:"
                signature.DistinguishedName = signature.Certificate.IssuerName.Name
    
                'Set the signature image source
                signature.SignImageSource = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\handSignature.png")
    
                'Set the signature font
                signature.SignDetailsFont = New PdfTrueTypeFont(New Font("Arial Unicode MS", 12f, FontStyle.Regular))
    
                'Set the document permission to forbid changes but allow form fill
                signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges | PdfCertificationFlags.AllowFormFill
    
                'Save to file
                doc.SaveToFile("TextAndImageSignature.pdf")
                doc.Close()
            End Sub
        End Class
    End Namespace