Introduction

public static void InsertPage()
{
  Console.WriteLine( "=== INSERT PAGE ===" );
  var outputFileName = "InsertPage.pdf";
  var outputPath = PagesSample.PagesSampleOutputDirectory + outputFileName;

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

    // Adds a title.
    var titleStyle = TextStyle.WithFont( pdfoutput.Fonts.GetStandardFont( StandardFontType.Helvetica ), 15d );
    page.AddParagraph( "Insert Page", titleStyle, new ParagraphStyle( ParagraphHorizontalAlignment.Center ) );

    // Defines a TextStyle to use for the following texts.
    var textStyle = TextStyle.WithFont( pdfoutput.Fonts.GetStandardFont( StandardFontType.Helvetica ), 18 );

    // Adds text on the first Page.
    page.AddText( "This text is on FIRST page.", new Point( 30, 100 ), textStyle );

    // Adds a new Page.
    page = pdfoutput.Pages.Add();

    // Adds text on the added Page.
    page.AddText( "This text is on the LAST page.", new Point( 30, 100 ), textStyle );

    // Inserts a new Page between the 2 firsts (at index 1).
    page = pdfoutput.Pages.Insert( 1 );

    // Adds text on the inserted Page.
    page.AddText( "This text is on an INSERTED page.", new Point( 30, 100 ), textStyle );

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