How to: Create a ZUGFeRD-Compliant PDF Invoice

• Jul 30, 2026

The PdfDocument.AttachZugferdInvoice method allows you to attach a ZUGFeRD-compliant XML to the PDF document. PDF Document API fully supports ZuGFeRD e-invoicing standard (including ZuGFeRD v2.5).

The following versions are supported:

Version	Description
Version1_0	Original ZUGFeRD 1.0 format
Version2_0_1	ZUGFeRD 2.0.1+
Version2_1	ZUGFeRD 2.1+ (compatible with v2.1 - v2.3)
Version2_3_2	ZUGFeRD 2.3.2+ (compatible with v2.3.2 - v2.5)

The following code sample attaches an invoice and saves the result:

C#

using (PdfDocumentProcessor pdfDocumentProcessor = new PdfDocumentProcessor())
{
    pdfDocumentProcessor.LoadDocument("Invoice.pdf");
    pdfDocumentProcessor.Document.AttachZugferdInvoice
        (File.ReadAllBytes("ZUGFeRD-invoice.xml"));
    pdfDocumentProcessor.SaveDocument("Invoice_Upd.pdf");
}

VB.NET

Using pdfDocumentProcessor As New PdfDocumentProcessor()
    pdfDocumentProcessor.LoadDocument("Invoice.pdf")
    pdfDocumentProcessor.Document.AttachZugferdInvoice
        (File.ReadAllBytes("ZUGFeRD-invoice.xml"))
    pdfDocumentProcessor.SaveDocument("Invoice_Upd.pdf")
End Using

Note

Consider the following when you attach a ZUGFeRD-compliant XML:

• The PdfDocumentProcessor does not validate the attached invoice.
• The AttachZugferdInvoice method does not convert the document to a PDF/A-3b compatible file. Make sure that your document is PDF/A-3b compliant.