public PdfFileAttachmentAnnotationFacade AddFileAttachmentAnnotation(
    PdfPoint point,
    PdfFileAttachment file
)

Public Function AddFileAttachmentAnnotation(
    point As PdfPoint,
    file As PdfFileAttachment
) As PdfFileAttachmentAnnotationFacade

using (PdfDocumentProcessor processor = new PdfDocumentProcessor())
{
    // Load a document
    processor.LoadDocument("..\\..\\Document.pdf");

    // Access page properties
    PdfPageFacade pageFacade = processor.DocumentFacade.Pages[0];

    // Create a file attachment object
    PdfFileAttachment attachment = new PdfFileAttachment()
    {
        CreationDate = DateTime.Now,
        Description = "This is my attach file.",
        FileName = "MyAttach.txt",
        Data = File.ReadAllBytes("..\\..\\FileToAttach.txt")
    };

    // Create a file attachment annotation
    PdfFileAttachmentAnnotationFacade pdfFileAttachment =
        pageFacade.AddFileAttachmentAnnotation(new PdfPoint(700,100), attachment);
    pdfFileAttachment.Author = "Sabella Jaida";
    pdfFileAttachment.Subject = "Attachment";

    // Save the result
    processor.SaveDocument("..\\..\\Result.pdf");
}

Using processor As New PdfDocumentProcessor()
  ' Load a document
  processor.LoadDocument("..\..\Document.pdf")

  ' Access page properties
  Dim pageFacade As PdfPageFacade = processor.DocumentFacade.Pages(0)

  ' Create a file attachment object
  Dim attachment As New PdfFileAttachment()
  With {.CreationDate = Date.Now,
    .Description = "This is my attach file.",
    .FileName = "MyAttach.txt",
    .Data = File.ReadAllBytes("..\..\FileToAttach.txt")}

  ' Create a file attachment annotation
    Dim pdfFileAttachment As PdfFileAttachmentAnnotationFacade =
       pageFacade.AddFileAttachmentAnnotation(New PdfPoint(700,100), attachment)
    pdfFileAttachment.Author = "Sabella Jaida"
    pdfFileAttachment.Subject = "Attachment"
  ' Save the result
  processor.SaveDocument("..\..\Result.pdf")
End Using