PM> Install-Package Spire.PDF

using Spire.Pdf.AutomaticFields;
using Spire.Pdf.Graphics;
using Spire.Pdf;
using System.Drawing;
using Spire.Pdf.License;

namespace AddPageNumbersToLeftCorner
{
    class Program
    {
        static void Main(string[] args)
        {
            // Apply your license key
            LicenseProvider.SetLicenseKey("License Key");

            // Create a PdfDocument object
            PdfDocument doc = new PdfDocument();

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

            // Create font, brush and pen, which determine the appearance of the page numbers to be added
            PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Times New Roman", 12, FontStyle.Regular), true);
            PdfBrush brush = PdfBrushes.Black;
            PdfPen pen = new PdfPen(brush, 1.0f);

            // Create a PdfPageNumberField object and a PdfPageCountField object
            PdfPageNumberField pageNumberField = new PdfPageNumberField();
            PdfPageCountField pageCountField = new PdfPageCountField();

            // Create a PdfCompositeField object to combine page count field and page number field in a single field
            PdfCompositeField compositeField = new PdfCompositeField(font, brush, "Page {0} of {1}", pageNumberField, pageCountField);

            // Get the page size
            SizeF pageSize = doc.Pages[0].Size;

            // Set the location of the composite field
            compositeField.Location = new PointF(72, pageSize.Height - 45);

            // Iterate through the pages in the document
            for (int i = 0; i < doc.Pages.Count; i++)
            {

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

                // Draw a line at the specified position
                page.Canvas.DrawLine(pen, 72, pageSize.Height - 50, pageSize.Width - 72, pageSize.Height - 50);

                // Draw the composite field on the page
                compositeField.Draw(page.Canvas);
            }

            // Save to a different PDF file
            doc.SaveToFile("AddPageNumbersToLeftCorner.pdf");

            // Dispose resources
            doc.Dispose();
        }
    }
}

using Spire.Pdf.AutomaticFields;
using Spire.Pdf.Graphics;
using Spire.Pdf;
using System.Drawing;
using Spire.Pdf.License;

namespace AddPageNumbersToCenter
{
    class Program
    {
        static void Main(string[] args)
        {
            // Apply your license key
            LicenseProvider.SetLicenseKey("License Key");

            // Create a PdfDocument object
            PdfDocument doc = new PdfDocument();

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

            // Create font, brush and pen, which determine the appearance of the page numbers to be added
            PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Times New Roman", 12, FontStyle.Regular), true);
            PdfBrush brush = PdfBrushes.Black;
            PdfPen pen = new PdfPen(brush, 1.0f);

            // Create a PdfPageNumberField object and a PdfPageCountField object
            PdfPageNumberField pageNumberField = new PdfPageNumberField();
            PdfPageCountField pageCountField = new PdfPageCountField();

            // Create a PdfCompositeField object to combine page count field and page number field in a single field
            PdfCompositeField compositeField = new PdfCompositeField(font, brush, "Page {0} of {1}", pageNumberField, pageCountField);


            // Iterate through the pages in the document
            for (int i = 0; i < doc.Pages.Count; i++)
            {

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

                // Get the page size
                SizeF pageSize = doc.Pages[i].Size;

                // Draw a line at the specified position
                page.Canvas.DrawLine(pen, 72, pageSize.Height - 50, pageSize.Width - 72, pageSize.Height - 50);

                // Measure the size the "Page X of Y"
                SizeF pageNumberSize = font.MeasureString(string.Format("Page {0} of {1}", i + 1, doc.Pages.Count));

                // Set the location of the composite field
                compositeField.Location = new PointF((pageSize.Width - pageNumberSize.Width) / 2, pageSize.Height - 45);

                // Draw the composite field on the page
                compositeField.Draw(page.Canvas);

            }

            // Save to a different PDF file
            doc.SaveToFile("AddPageNumbersToCenter.pdf");

            // Dispose resources
            doc.Dispose();
        }
    }
}

using Spire.Pdf.AutomaticFields;
using Spire.Pdf.Graphics;
using Spire.Pdf;
using System.Drawing;
using Spire.Pdf.License;

namespace AddPageNumbersToRigthCorner
{
    class Program
    {
        static void Main(string[] args)
        {
            // Apply your license key
            LicenseProvider.SetLicenseKey("License Key");

            // Create a PdfDocument object
            PdfDocument doc = new PdfDocument();

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

            // Create font, brush and pen, which determine the appearance of the page numbers to be added
            PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Times New Roman", 12, FontStyle.Regular), true);
            PdfBrush brush = PdfBrushes.Black;
            PdfPen pen = new PdfPen(brush, 1.0f);

            // Create a PdfPageNumberField object and a PdfPageCountField object
            PdfPageNumberField pageNumberField = new PdfPageNumberField();
            PdfPageCountField pageCountField = new PdfPageCountField();

            // Create a PdfCompositeField object to combine page count field and page number field in a single field
            PdfCompositeField compositeField = new PdfCompositeField(font, brush, "Page {0} of {1}", pageNumberField, pageCountField);


            // Iterate through the pages in the document
            for (int i = 0; i < doc.Pages.Count; i++)
            {

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

                // Get the page size
                SizeF pageSize = doc.Pages[i].Size;

                // Draw a line at the specified position
                page.Canvas.DrawLine(pen, 72, pageSize.Height - 50, pageSize.Width - 72, pageSize.Height - 50);

                // Measure the size the "Page X of Y"
                SizeF pageNumberSize = font.MeasureString(string.Format("Page {0} of {1}", i + 1, doc.Pages.Count));

                // Set the location of the composite field
                compositeField.Location = new PointF(pageSize.Width - pageNumberSize.Width - 72, pageSize.Height - 45);

                // Draw the composite field on the page
                compositeField.Draw(page.Canvas);

            }

            // Save to a different PDF file
            doc.SaveToFile("AddPageNumbersToRigthCorner.pdf");

            // Dispose resources
            doc.Dispose();
        }
    }
}

PM> Install-Package Spire.PDF

using Spire.Pdf;
using Spire.Pdf.Actions;
using Spire.Pdf.Annotations;
using Spire.Pdf.General;
using Spire.Pdf.Graphics;
using System;
using System.Drawing;

namespace TableOfContents
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Initialize an instance of the PdfDocument class
            PdfDocument doc = new PdfDocument();
            //Load a PDF document
            doc.LoadFromFile("Sample.PDF");

            //Get the page count of the document
            int pageCount = doc.Pages.Count;

            //Insert a new page into the pdf document as the first page
            PdfPageBase tocPage = doc.Pages.Insert(0);

            //Draw TOC title on the new page
            string title = "Table of Contents";
            PdfTrueTypeFont titleFont = new PdfTrueTypeFont(new Font("Arial", 20, FontStyle.Bold));
            PdfStringFormat centerAlignment = new PdfStringFormat(PdfTextAlignment.Center, PdfVerticalAlignment.Middle);
            PointF location = new PointF(tocPage.Canvas.ClientSize.Width / 2, titleFont.MeasureString(title).Height + 10);
            tocPage.Canvas.DrawString(title, titleFont, PdfBrushes.CornflowerBlue, location, centerAlignment);

            //Draw TOC content on the new page
            PdfTrueTypeFont titlesFont = new PdfTrueTypeFont(new Font("Arial", 14));
            String[] titles = new String[pageCount];
            for (int i = 0; i < titles.Length; i++)
            {
                titles[i] = string.Format("This is page {0}", i + 1);
            }
            float y = titleFont.MeasureString(title).Height + 10;
            float x = 0;

            //Draw page numbers of the target pages on the new page
            for (int i = 1; i <= pageCount; i++)
            {
                string text = titles[i - 1];
                SizeF titleSize = titlesFont.MeasureString(text);

                PdfPageBase navigatedPage = doc.Pages[i];

                string pageNumText = (i + 1).ToString();
                SizeF pageNumTextSize = titlesFont.MeasureString(pageNumText);
                tocPage.Canvas.DrawString(text, titlesFont, PdfBrushes.CadetBlue, 0, y);
                float dotLocation = titleSize.Width + 2 + x;
                float pageNumlocation = tocPage.Canvas.ClientSize.Width - pageNumTextSize.Width;
                for (float j = dotLocation; j < pageNumlocation; j++)
                {
                    if (dotLocation >= pageNumlocation)
                    {
                        break;
                    }
                    tocPage.Canvas.DrawString(".", titlesFont, PdfBrushes.Gray, dotLocation, y);
                    dotLocation += 3;
                }
                tocPage.Canvas.DrawString(pageNumText, titlesFont, PdfBrushes.CadetBlue, pageNumlocation, y);

                //Add actions that will take you to the target pages when clicked on to the new page
                location = new PointF(0, y);
                RectangleF titleBounds = new RectangleF(location, new SizeF(tocPage.Canvas.ClientSize.Width, titleSize.Height));
                PdfDestination Dest = new PdfDestination(navigatedPage, new PointF(-doc.PageSettings.Margins.Top, -doc.PageSettings.Margins.Left));
                PdfActionAnnotation action = new PdfActionAnnotation(titleBounds, new PdfGoToAction(Dest));
                action.Border = new PdfAnnotationBorder(0);
                (tocPage as PdfNewPage).Annotations.Add(action);
                y += titleSize.Height + 10;
            }

            //Save the result pdf document
            doc.SaveToFile("AddTableOfContents.pdf");
            doc.Close();
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Actions
Imports Spire.Pdf.Annotations
Imports Spire.Pdf.General
Imports Spire.Pdf.Graphics
Imports System.Drawing

Namespace TableOfContents
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Initialize an instance of the PdfDocument class
            Dim doc As PdfDocument = New PdfDocument()
            'Load a PDF document
            doc.LoadFromFile("Sample.PDF")

            'Get the page count of the document
            Dim pageCount As Integer = doc.Pages.Count

            'Insert a new page into the pdf document as the first page
            Dim tocPage As PdfPageBase = doc.Pages.Insert(0)

            'Draw TOC title on the new page
            Dim title = "Table of Contents"
            Dim titleFont As PdfTrueTypeFont = New PdfTrueTypeFont(New Font("Arial", 20, FontStyle.Bold))
            Dim centerAlignment As PdfStringFormat = New PdfStringFormat(PdfTextAlignment.Center, PdfVerticalAlignment.Middle)
            Dim location As PointF = New PointF(tocPage.Canvas.ClientSize.Width / 2, titleFont.MeasureString(title).Height + 10)
            tocPage.Canvas.DrawString(title, titleFont, PdfBrushes.CornflowerBlue, location, centerAlignment)

            'Draw TOC content on the new page
            Dim titlesFont As PdfTrueTypeFont = New PdfTrueTypeFont(New Font("Arial", 14))
            Dim titles = New String(pageCount - 1) {}
            For i = 0 To titles.Length - 1
                titles(i) = String.Format("This is page {0}", i + 1)
            Next
            Dim y As Single = titleFont.MeasureString(title).Height + 10
            Dim x As Single = 0

            'Draw page numbers of the target pages on the new page
            For i = 1 To pageCount
                Dim text = titles(i - 1)
                Dim titleSize As SizeF = titlesFont.MeasureString(text)

                Dim navigatedPage As PdfPageBase = doc.Pages(i)

                Dim pageNumText As String = (i + 1).ToString()
                Dim pageNumTextSize As SizeF = titlesFont.MeasureString(pageNumText)
                tocPage.Canvas.DrawString(text, titlesFont, PdfBrushes.CadetBlue, 0, y)
                Dim dotLocation = titleSize.Width + 2 + x
                Dim pageNumlocation As Single = tocPage.Canvas.ClientSize.Width - pageNumTextSize.Width
                For j = dotLocation To pageNumlocation - 1
                    If dotLocation >= pageNumlocation Then
                        Exit For
                    End If
                    tocPage.Canvas.DrawString(".", titlesFont, PdfBrushes.Gray, dotLocation, y)
                    dotLocation += 3
                Next
                tocPage.Canvas.DrawString(pageNumText, titlesFont, PdfBrushes.CadetBlue, pageNumlocation, y)

                'Add actions that will take you to the target pages when clicked on to the new page
                location = New PointF(0, y)
                Dim titleBounds As RectangleF = New RectangleF(location, New SizeF(tocPage.Canvas.ClientSize.Width, titleSize.Height))
                Dim Dest As PdfDestination = New PdfDestination(navigatedPage, New PointF(-doc.PageSettings.Margins.Top, -doc.PageSettings.Margins.Left))
                Dim action As PdfActionAnnotation = New PdfActionAnnotation(titleBounds, New PdfGoToAction(Dest))
                action.Border = New PdfAnnotationBorder(0)
                TryCast(tocPage, PdfNewPage).Annotations.Add(action)
                y += titleSize.Height + 10
            Next

            'Save the result pdf document
            doc.SaveToFile("AddTableOfContents.pdf")
            doc.Close()
        End Sub
    End Class
End Namespace