PM> Install-Package Spire.Presentation

using Spire.Presentation;
using System.IO;
using System.Text;
namespace ExtractText
{
    class Program
    {
        static void Main(string[] args)
        {
            //Initialize an instance of the Presentation class
            Presentation presentation = new Presentation();

            //Load a sample PowerPoint document
            presentation.LoadFromFile("Island.pptx");
            //Create a StringBuilder instance
            StringBuilder sb = new StringBuilder();

            //Iterate through each slide in the document
            foreach (ISlide slide in presentation.Slides)
            {
                //Iterate through each shape in each slide
                foreach (IShape shape in slide.Shapes)
                {
                    //Check if the shape is of IAutoShape type
                    if (shape is IAutoShape)
                    {
                        //Iterate through all paragraphs in each shape
                        foreach (TextParagraph tp in (shape as IAutoShape).TextFrame.Paragraphs)
                        {
                            //Extract text and save to StringBuilder instance
                            sb.AppendLine(tp.Text);
                        }
                    }
                }
            }
            //Create a new txt file to save the extracted text
            File.WriteAllText("ExtractText.txt", sb.ToString());
        }
    }
}

Imports Spire.Presentation
Imports System.IO
Imports System.Text

Namespace ExtractText
    Class Program
        Private Shared Sub Main(ByVal args() As String)

            'Initialize an instance of the Presentation class
            Dim presentation As Presentation = New Presentation

            'Load a sample PowerPoint document
            presentation.LoadFromFile("Island.pptx")

            'Create a StringBuilder instance
            Dim sb As StringBuilder = New StringBuilder

            'Iterate through each slide in the document
            For Each slide As ISlide In presentation.Slides

                'Iterate through each shape in each slide
                For Each shape As IShape In slide.Shapes

                    'Check if the shape is of IAutoShape type
                    If (TypeOf shape Is IAutoShape) Then

                        'Iterate through all paragraphs in each shape
                        For Each tp As TextParagraph In CType(shape, IAutoShape).TextFrame.Paragraphs

                            'Extract text and save to StringBuilder instance
                            sb.AppendLine(tp.Text)
                        Next
                    End If
                Next
            Next

            'Create a new txt file to save the extracted text
            File.WriteAllText("ExtractText.txt", sb.ToString)
        End Sub
    End Class
End Namespace

PM> Install-Package Spire.Presentation

using Spire.Presentation;
using Spire.Presentation.Drawing;
using System.Drawing;

namespace CreateNumberedList
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation object
            Presentation presentation = new Presentation();
            //Get the first slide
            ISlide slide = presentation.Slides[0];

            //Add a shape to the slide and set the shape style
            IAutoShape shape = slide.Shapes.AppendShape(ShapeType.Rectangle, new RectangleF(50, 50, 300, 200));
            shape.Fill.FillType = FillFormatType.None;
            shape.Line.FillType= FillFormatType.None;

            //Add text to the default paragraph
            TextParagraph paragraph = shape.TextFrame.Paragraphs[0];
            paragraph.Text = "Required Web Development Skills:";
            paragraph.Alignment = TextAlignmentType.Left;
            paragraph.TextRanges[0].Fill.FillType = FillFormatType.Solid;
            paragraph.TextRanges[0].Fill.SolidColor.Color = Color.Black;

            //Specify the list items
            string[] listItems = new string[] {
                " Command-line Unix",
                " Vim",
                " HTML",
                " CSS",
                " Python",
                " JavaScript",
                " SQL"
            };

            //Create a numbered list
            foreach (string item in listItems)
            {
                TextParagraph textParagraph = new TextParagraph();
                textParagraph.Text = item;
                textParagraph.Alignment = TextAlignmentType.Left;
                textParagraph.TextRanges[0].Fill.FillType = FillFormatType.Solid;
                textParagraph.TextRanges[0].Fill.SolidColor.Color = Color.Black;

                textParagraph.BulletType = TextBulletType.Numbered;
                textParagraph.BulletStyle = NumberedBulletStyle.BulletArabicPeriod;
                shape.TextFrame.Paragraphs.Append(textParagraph);
            }

            //Save the result document
            presentation.SaveToFile("NumberedList.pptx", FileFormat.Pptx2013);
        }
    }
}

Imports Spire.Presentation
Imports Spire.Presentation.Drawing
Imports System.Drawing

Namespace CreateNumberedList
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Presentation object
            Dim presentation As Presentation = New Presentation()
            'Get the first slide
            Dim slide As ISlide = presentation.Slides(0)

            'Add a shape to the slide and set the shape style
            Dim shape As IAutoShape = slide.Shapes.AppendShape(ShapeType.Rectangle, New RectangleF(50, 50, 300, 200))
            shape.Fill.FillType = FillFormatType.None
            shape.Line.FillType = FillFormatType.None

            'Add text to the default paragraph
            Dim paragraph As TextParagraph = shape.TextFrame.Paragraphs(0)
            paragraph.Text = "Required Web Development Skills:"
            paragraph.Alignment = TextAlignmentType.Left
            paragraph.TextRanges(0).Fill.FillType = FillFormatType.Solid
            paragraph.TextRanges(0).Fill.SolidColor.Color = Color.Black

            'Specify the list items
            Dim listItems = New String() {" Command-line Unix", " Vim", " HTML", " CSS", " Python", " JavaScript", " SQL"}

            'Create a numbered list
            For Each item In listItems
                Dim textParagraph As TextParagraph = New TextParagraph()
                textParagraph.Text = item
                textParagraph.Alignment = TextAlignmentType.Left
                textParagraph.TextRanges(0).Fill.FillType = FillFormatType.Solid
                textParagraph.TextRanges(0).Fill.SolidColor.Color = Color.Black

                textParagraph.BulletType = TextBulletType.Numbered
                textParagraph.BulletStyle = NumberedBulletStyle.BulletArabicPeriod
                shape.TextFrame.Paragraphs.Append(textParagraph)
            Next

            'Save the result document
            presentation.SaveToFile("NumberedList.pptx", FileFormat.Pptx2013)
        End Sub
    End Class
End Namespace

using Spire.Presentation;
using Spire.Presentation.Drawing;
using System.Drawing;

namespace CreateSymbolBulletedList
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation object
            Presentation presentation = new Presentation();
            //Get the first slide
            ISlide slide = presentation.Slides[0];

            //Add a shape to the slide and set the shape style
            IAutoShape shape = slide.Shapes.AppendShape(ShapeType.Rectangle, new RectangleF(50, 50, 350, 200));
            shape.Fill.FillType = FillFormatType.None;
            shape.Line.FillType = FillFormatType.None;

            //Add text to the default paragraph
            TextParagraph paragraph = shape.TextFrame.Paragraphs[0];
            paragraph.Text = "Computer Science Subjects:";
            paragraph.Alignment = TextAlignmentType.Left;
            paragraph.TextRanges[0].Fill.FillType = FillFormatType.Solid;
            paragraph.TextRanges[0].Fill.SolidColor.Color = Color.Black;

            //Specify the list items
            string[] listItems = new string[] {
                " Data Structure",
                " Algorithm",
                " Computer Networks",
                " Operating System",
                " Theory of Computations",
                " C Programming",
                " Computer Organization and Architecture"
            };

            //Create a symbol bulleted list
            foreach (string item in listItems)
            {
                TextParagraph textParagraph = new TextParagraph();
                textParagraph.Text = item;
                textParagraph.Alignment = TextAlignmentType.Left;
                textParagraph.TextRanges[0].Fill.FillType = FillFormatType.Solid;
                textParagraph.TextRanges[0].Fill.SolidColor.Color = Color.Black;
                textParagraph.BulletType = TextBulletType.Symbol;
                shape.TextFrame.Paragraphs.Append(textParagraph);
            }

            //Save the result document
            presentation.SaveToFile("SymbolBulletedList.pptx", FileFormat.Pptx2013);
        }
    }
}

Imports Spire.Presentation
Imports Spire.Presentation.Drawing
Imports System.Drawing

Namespace CreateSymbolBulletedList
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Presentation object
            Dim presentation As Presentation = New Presentation()
            'Get the first slide
            Dim slide As ISlide = presentation.Slides(0)

            'Add a shape to the slide and set the shape style
            Dim shape As IAutoShape = slide.Shapes.AppendShape(ShapeType.Rectangle, New RectangleF(50, 50, 350, 200))
            shape.Fill.FillType = FillFormatType.None
            shape.Line.FillType = FillFormatType.None

            'Add text to the default paragraph
            Dim paragraph As TextParagraph = shape.TextFrame.Paragraphs(0)
            paragraph.Text = "Computer Science Subjects:"
            paragraph.Alignment = TextAlignmentType.Left
            paragraph.TextRanges(0).Fill.FillType = FillFormatType.Solid
            paragraph.TextRanges(0).Fill.SolidColor.Color = Color.Black

            'Specify the list items
            Dim listItems = New String() {" Data Structure", " Algorithm", " Computer Networks", " Operating System", " Theory of Computations", " C Programming", " Computer Organization and Architecture"}

            'Create a symbol bulleted list
            For Each item In listItems
                Dim textParagraph As TextParagraph = New TextParagraph()
                textParagraph.Text = item
                textParagraph.Alignment = TextAlignmentType.Left
                textParagraph.TextRanges(0).Fill.FillType = FillFormatType.Solid
                textParagraph.TextRanges(0).Fill.SolidColor.Color = Color.Black
                textParagraph.BulletType = TextBulletType.Symbol
                shape.TextFrame.Paragraphs.Append(textParagraph)
            Next

            'Save the result document
            presentation.SaveToFile("SymbolBulletedList.pptx", FileFormat.Pptx2013)
        End Sub
    End Class
End Namespace

using Spire.Presentation;
using Spire.Presentation.Drawing;
using System.Drawing;

namespace CreateImageBulletedList
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation object
            Presentation presentation = new Presentation();
            //Get the first slide
            ISlide slide = presentation.Slides[0];

            //Add a shape to the slide and set the shape style
            IAutoShape shape = slide.Shapes.AppendShape(ShapeType.Rectangle, new RectangleF(50, 50, 400, 180));
            shape.Fill.FillType = FillFormatType.None;
            shape.Line.FillType = FillFormatType.None;

            //Add text to the default paragraph
            TextParagraph paragraph = shape.TextFrame.Paragraphs[0];
            paragraph.Text = "Project Task To-Do List:";
            paragraph.Alignment = TextAlignmentType.Left;
            paragraph.TextRanges[0].Fill.FillType = FillFormatType.Solid;
            paragraph.TextRanges[0].Fill.SolidColor.Color = Color.Black;

            //Specify the list items
            string[] listItems = new string[] {
                " Define projects and tasks you're working on",
                " Assign people to tasks",
                " Define the priority levels of your tasks",
                " Keep track of the progress status of your tasks",
                " Mark tasks as done when completed"
            };

            //Create an image bulleted list
            foreach (string item in listItems)
            {
                TextParagraph textParagraph = new TextParagraph();
                textParagraph.Text = item;
                textParagraph.Alignment = TextAlignmentType.Left;
                textParagraph.TextRanges[0].Fill.FillType = FillFormatType.Solid;
                textParagraph.TextRanges[0].Fill.SolidColor.Color = Color.Black;
                textParagraph.BulletType = TextBulletType.Picture;
                IImageData image = presentation.Images.Append(Image.FromFile("icon.png"));
                textParagraph.BulletPicture.EmbedImage = image;
                shape.TextFrame.Paragraphs.Append(textParagraph);
            }

            //Save the result document
            presentation.SaveToFile("ImageBulletedList.pptx", FileFormat.Pptx2013);
        }
    }
}

Imports Spire.Presentation
Imports Spire.Presentation.Drawing
Imports System.Drawing

Namespace CreateImageBulletedList
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Presentation object
            Dim presentation As Presentation = New Presentation()
            'Get the first slide
            Dim slide As ISlide = presentation.Slides(0)

            'Add a shape to the slide and set the shape style
            Dim shape As IAutoShape = slide.Shapes.AppendShape(ShapeType.Rectangle, New RectangleF(50, 50, 400, 180))
            shape.Fill.FillType = FillFormatType.None
            shape.Line.FillType = FillFormatType.None

            'Add text to the default paragraph
            Dim paragraph As TextParagraph = shape.TextFrame.Paragraphs(0)
            paragraph.Text = "Project Task To-Do List:"
            paragraph.Alignment = TextAlignmentType.Left
            paragraph.TextRanges(0).Fill.FillType = FillFormatType.Solid
            paragraph.TextRanges(0).Fill.SolidColor.Color = Color.Black

            'Specify the list items
            Dim listItems = New String() {" Define projects and tasks you're working on", " Assign people to tasks", " Define the priority levels of your tasks", " Keep track of the progress status of your tasks", " Mark tasks as done when completed"}

            'Create an image bulleted list
            For Each item In listItems
                Dim textParagraph As TextParagraph = New TextParagraph()
                textParagraph.Text = item
                textParagraph.Alignment = TextAlignmentType.Left
                textParagraph.TextRanges(0).Fill.FillType = FillFormatType.Solid
                textParagraph.TextRanges(0).Fill.SolidColor.Color = Color.Black
                textParagraph.BulletType = TextBulletType.Picture
                Dim image As IImageData = presentation.Images.Append(Image.FromFile("icon.png"))
                textParagraph.BulletPicture.EmbedImage = image
                shape.TextFrame.Paragraphs.Append(textParagraph)
            Next

            'Save the result document
            presentation.SaveToFile("ImageBulletedList.pptx", FileFormat.Pptx2013)
        End Sub
    End Class
End Namespace