PM> Install-Package Spire.PDF

using Spire.Pdf;
using Spire.Pdf.Attachments;
using System.Net.Mail;

namespace ExtractAttachments
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a PdfDocument object
            PdfDocument doc = new PdfDocument();

            //Load a PDF file that contains attachments
            doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Attachments.pdf");

            //Get the attachment collection of the PDF document
            PdfAttachmentCollection attachments = doc.Attachments;

            //Specific output folder path
            string outputFolder = "C:\\Users\\Administrator\\Desktop\\output\\";

            //Loop through the collection
            for (int i = 0; i < attachments.Count; i++)
            {   
	          //Write attachment to a file
                File.WriteAllBytes(outputFolder + attachments[i].FileName, attachments[i].Data);
            }
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Attachments
Imports System.Net.Mail
 
Namespace ExtractAttachments
    Class Program
        Shared  Sub Main(ByVal args() As String)
            'Create a PdfDocument object
            Dim doc As PdfDocument =  New PdfDocument() 
 
            'Load a PDF file that contains attachments
            doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Attachments.pdf")
 
            'Get the attachment collection of the PDF document
            Dim attachments As PdfAttachmentCollection =  doc.Attachments 
 
            'Specific output folder path
            Dim outputFolder As String =  "C:\\Users\\Administrator\\Desktop\\output\\" 
 
            'Loop through the collection
            Dim i As Integer
            For  i = 0 To  attachments.Count- 1  Step  i + 1

	 'Write attachment to a file
                File.WriteAllBytes(outputFolder + attachments(i).FileName, attachments(i).Data)
            Next
        End Sub
    End Class
End Namespace

using Spire.Pdf;
using Spire.Pdf.Annotations;

namespace ExtractAnnotationAttachments
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a PdfDocument object
            PdfDocument doc = new PdfDocument();

            //Load a PDF file that contains attachments
            doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\AnnotationAttachments.pdf");

            //Specific output folder path
            string outputFolder = "C:\\Users\\Administrator\\Desktop\\Output\\";

            //Loop through the pages
            for (int i = 0; i < doc.Pages.Count; i++)
            {
                //Get the annotation collection
                PdfAnnotationCollection collection = doc.Pages[i].AnnotationsWidget;

                //Loop through the annotations
                for (int j = 0; j < collection.Count; j++)
                {
                    //Determine if an annotation is an instance of PdfAttachmentAnnotationWidget
                    if (collection[j] is PdfAttachmentAnnotationWidget)
                    {
                        //Write annotation attachment to a file
                        PdfAttachmentAnnotationWidget attachmentAnnotation = (PdfAttachmentAnnotationWidget)collection[j];
                        String fileName = Path.GetFileName(attachmentAnnotation.FileName);
                        File.WriteAllBytes(outputFolder + fileName, attachmentAnnotation.Data);
                    }
                }
            }
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Annotations
 
Namespace ExtractAnnotationAttachments
    Class Program
        Shared  Sub Main(ByVal args() As String)
            'Create a PdfDocument object
            Dim doc As PdfDocument =  New PdfDocument() 
 
            'Load a PDF file that contains attachments
            doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\AnnotationAttachments.pdf")
 
            'Specific output folder path
            Dim outputFolder As String =  "C:\\Users\\Administrator\\Desktop\\Output\\" 
 
            'Loop through the pages
            Dim i As Integer
            For  i = 0 To  doc.Pages.Count- 1  Step  i + 1
                'Get the annotation collection
                Dim collection As PdfAnnotationCollection =  doc.Pages(i).AnnotationsWidget 
 
                'Loop through the annotations
                Dim j As Integer
                For  j = 0 To  collection.Count- 1  Step  j + 1
                    'Determine if an annotation is an instance of PdfAttachmentAnnotationWidget
                    If TypeOf collection(j) Is PdfAttachmentAnnotationWidget Then
                        'Write annotation attachment to a file
                        Dim attachmentAnnotation As PdfAttachmentAnnotationWidget = CType(collection(j), PdfAttachmentAnnotationWidget)
                        Dim fileName As String =  Path.GetFileName(attachmentAnnotation.FileName) 
                        File.WriteAllBytes(outputFolder + fileName, attachmentAnnotation.Data)
                    End If
                Next
            Next
        End Sub
    End Class
End Namespace

PM> Install-Package Spire.PDF

using Spire.Pdf;
using Spire.Pdf.Attachments;

namespace AttachFilesToPDF
{
    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");

            //Create a PdfAttachment object based on an external file
            PdfAttachment attachment = new PdfAttachment("C:\\Users\\Administrator\\Desktop\\Data.xlsx");

            //Add the attachment to PDF
            doc.Attachments.Add(attachment);

            //Save to file
            doc.SaveToFile("Attachment.pdf");
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Attachments
 
Namespace AttachFilesToPDF
    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")
 
            'Create a PdfAttachment object based on an external file
            Dim attachment As PdfAttachment =  New PdfAttachment("C:\\Users\\Administrator\\Desktop\\Data.xlsx") 
 
            'Add the attachment to PDF
            doc.Attachments.Add(attachment)
 
            'Save to file
            doc.SaveToFile("Attachment.pdf")
        End Sub
    End Class
End Namespace

using Spire.Pdf;
using Spire.Pdf.Annotations;
using Spire.Pdf.Graphics;
using System;
using System.Drawing;
using System.IO;

namespace AnnotationAttachment
{
    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");

            //Get a specific page
            PdfPageBase page = doc.Pages[0];

            //Draw a label on PDF
            String label = "Here is the report:";
            PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial", 13f, FontStyle.Bold), true); 
            float x = 35;
            float y = doc.Pages[0].ActualSize.Height - 220;
            page.Canvas.DrawString(label, font, PdfBrushes.Red, x, y);

            //Create a PdfAttachmentAnnotation object based on an external file
            String filePath = "C:\\Users\\Administrator\\Desktop\\Report.pptx";
            byte[] data = File.ReadAllBytes(filePath);
            SizeF size = font.MeasureString(label);
            RectangleF bounds = new RectangleF((float)(x + size.Width + 5), (float)y, 10, 15);
            PdfAttachmentAnnotation annotation = new PdfAttachmentAnnotation(bounds, "Report.docx", data);
            annotation.Color = Color.Purple;
            annotation.Flags = PdfAnnotationFlags.Default;
            annotation.Icon = PdfAttachmentIcon.Graph;
            annotation.Text = "Click here to open the file";

            //Add the attachment annotation to PDF
            page.AnnotationsWidget.Add(annotation);

            //Save to file
            doc.SaveToFile("Annotation.pdf");
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Annotations
Imports Spire.Pdf.Graphics
Imports System
Imports System.Drawing
Imports System.IO
 
Namespace AnnotationAttachment
    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")
 
            'Get a specific page
            Dim page As PdfPageBase =  doc.Pages(0) 
 
            'Draw a label on PDF
            Dim label As String =  "Here is the report:" 
            Dim font As PdfTrueTypeFont =  New PdfTrueTypeFont(New Font("Arial",13f,FontStyle.Bold),True) 
            Dim x As single =  35 
            Dim y As single =  doc.Pages(0).ActualSize.Height - 220 
            page.Canvas.DrawString(label, font, PdfBrushes.Red, x, y)
 
            'Create a PdfAttachmentAnnotation object based on an external file
            Dim filePath As String =  "C:\\Users\\Administrator\\Desktop\\Report.pptx" 
            Dim data() As Byte =  File.ReadAllBytes(filePath) 
            Dim size As SizeF =  font.MeasureString(label) 
            Dim bounds As RectangleF =  New RectangleF(CType((x + size.Width + 5),(single)y,10,15, single)) 
            Dim annotation As PdfAttachmentAnnotation =  New PdfAttachmentAnnotation(bounds,"Report.docx",data) 
            annotation.Color = Color.Purple
            annotation.Flags = PdfAnnotationFlags.Default
            annotation.Icon = PdfAttachmentIcon.Graph
            annotation.Text = "Click here to open the file"
 
            'Add the attachment annotation to PDF
            page.AnnotationsWidget.Add(annotation)
 
            'Save to file
            doc.SaveToFile("Annotation.pdf")
        End Sub
    End Class
End Namespace

using Spire.Pdf;
using Spire.Pdf.Attachments;

namespace RemoveAttachments
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a PdfDocument object
            PdfDocument doc = new PdfDocument();

            //Load a PDF file
            doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Attachment.pdf");

            //Get attachment collection
            PdfAttachmentCollection attachments = doc.Attachments;

            //Remove a specific attachment
            attachments.RemoveAt(0);

            //Remove all attachments
            //attachments.Clear();

            //save to file
            doc.SaveToFile("DeleteAttachments.pdf");
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Attachments
 
Namespace RemoveAttachments
    Class Program
        Shared  Sub Main(ByVal args() As String)
            'Create a PdfDocument object
            Dim doc As PdfDocument =  New PdfDocument() 
 
            'Load a PDF file
            doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Attachment.pdf")
 
            'Get attachment collection
            Dim attachments As PdfAttachmentCollection =  doc.Attachments 
 
            'Remove a specific attachment
            attachments.RemoveAt(0)
 
            'Remove all attachments
            'attachments.Clear();
 
            'save to file
            doc.SaveToFile("DeleteAttachments.pdf")
        End Sub
    End Class
End Namespace

using Spire.Pdf;
using Spire.Pdf.Annotations;

namespace RemoveAnnotationAttachments
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a PdfDocument object
            PdfDocument doc = new PdfDocument();

            //Load a PDF file
            doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Annotation.pdf");

            //Loop through the pages
            for (int i = 0; i < doc.Pages.Count; i++)
            {
                //Get the annotation collection
                PdfAnnotationCollection annotationCollection = doc.Pages[i].AnnotationsWidget;

                //Loop through the annotations
                for (int j = 0; j < annotationCollection.Count; j++)
                {
                    //Determine if an annotation is an instance of PdfAttachmentAnnotationWidget
                    if (annotationCollection[j] is PdfAttachmentAnnotationWidget)
                    {
                        //Remove the annotation attachment 
                        annotationCollection.Remove((PdfAnnotation)annotationCollection[j]);
                    }
                }
            }

            //Save to file
            doc.SaveToFile("DeleteAnnotationAttachments.pdf");
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Annotations
 
Namespace RemoveAnnotationAttachments
    Class Program
        Shared  Sub Main(ByVal args() As String)
            'Create a PdfDocument object
            Dim doc As PdfDocument =  New PdfDocument() 
 
            'Load a PDF file
            doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Annotation.pdf")
 
            'Loop through the pages
            Dim i As Integer
            For  i = 0 To  doc.Pages.Count- 1  Step  i + 1
                'Get the annotation collection
                Dim annotationCollection As PdfAnnotationCollection =  doc.Pages(i).AnnotationsWidget 
 
                'Loop through the annotations
                Dim j As Integer
                For  j = 0 To  annotationCollection.Count- 1  Step  j + 1
                    'Determine if an annotation is an instance of PdfAttachmentAnnotationWidget
                    If TypeOf annotationCollection(j) Is PdfAttachmentAnnotationWidget Then
                        'Remove the annotation attachment 
                        annotationCollection.Remove(CType(annotationCollection(j), PdfAnnotation))
                    End If
                Next
            Next
 
            'Save to file
            doc.SaveToFile("DeleteAnnotationAttachments.pdf")
        End Sub
    End Class
End Namespace