Introduction

public static void AddBookmarks()
{
  Console.WriteLine( "=== ADD BOOKMARKS ===" );

  var outputFileName = "AddBookmarks.pdf";
  var outputPath = BookmarksSample.BookmarksSampleOutputDirectory + outputFileName;

  // Creates a PdfDocument.
  using( var pdfoutput = PdfDocument.Create( outputPath ) )
  {
    // Gets the first Page.
    var firstPage = pdfoutput.Pages.First();

    // Adds a title.
    var textStyle = TextStyle.WithFont( pdfoutput.Fonts.GetStandardFont( StandardFontType.Helvetica ), 15d );
    firstPage.AddParagraph( "Add bookmarks", textStyle, new ParagraphStyle( ParagraphHorizontalAlignment.Center ) );

    // Adds 2 more Pages.
    var secondPage = pdfoutput.Pages.Add();
    var thirdPage = pdfoutput.Pages.Add();

    // Adds text to the 3 first Pages
    firstPage.AddText( "This is the FIRST page", new Point( 100, 100 ) );
    secondPage.AddText( "This is the SECOND page", new Point( 100, 100 ) );
    thirdPage.AddText( "This is the THIRD page", new Point( 100, 100 ) );

    // Adds the first Bookmark, which targets the top of the first Page.
    var firstBookmark = new Bookmark( "Bookmark1" ) { TargetPage = 0 };
    pdfoutput.Bookmarks.Add( firstBookmark );

    // Adds a second Bookmark, which targets positionY = 100 on the second Page.
    var secondBookmark = new Bookmark( "Bookmark2" )
    {
      TargetPage = 1,
      TargetPageLocation = new Point( 0, 100 ),
      IsBold = true,
      IsItalic = true,
      TitleColor = Color.Red
    };
    pdfoutput.Bookmarks.Add( secondBookmark );

    // Adds a third Bookmark, which is a child of the second Bookmark & targets positionY = 105 on the third Page.
    var thirdBookmark = new Bookmark( "Bookmark3" )
    {
      TargetPage = 2,
      TargetPageLocation = new Point( 0, 105 ),
      IsItalic = true,
    };
    secondBookmark.Children.Add( thirdBookmark );

    // Saves the output document.
    pdfoutput.Save();
    Console.WriteLine( $"Info exported to path: {outputFileName}" );
  }
}