ลายเซ็นดิจิทัล PDF

   var esign_doc = new Document("My File.pdf");
    var page = esign_doc.PdfDocument.Pages[1];
    // Create text stamp
    TextStamp textStamp = new TextStamp(getFormattedText("digital signature text"));
    // Set whether stamp is background
    // textStamp.Background = true;
    textStamp.HorizontalAlignment = HorizontalAlignment.Right;
    textStamp.VerticalAlignment = VerticalAlignment.Bottom;
    textStamp.TextAlignment = HorizontalAlignment.Center;
    textStamp.TextState.Font = FontRepository.FindFont("Arial");
    textStamp.TextState.FontSize = 50;
    textStamp.Width = page.PageInfo.Width / 3;
    textStamp.TextState.ForegroundColor = Color.FromRgb(System.Drawing.Color.Aqua);
    page.AddStamp(textStamp);

    esign_doc.Save("esignedFile.pdf", SaveFormat.Pdf);