Attach files to the PDF

The PDF file format offers the possibility of embedding files in the document so that they can then be downloaded as stand-alone documents. Electronic invoices, for example, can be sent as a “human-readable” PDF with an attached computer-readable description (as XML).

Any number of files can be attached, but only one ZUGFeRD invoice.

Attach files

<AttachFile description="A nice view"
            type="application/pdf"
            filename="ocean.pdf" />

This command is used to attach a file to the PDF. The type is the mime type of the attached file.

attachfile
This is what attached files look like in Adobe Acrobat.

Attach ZUGFeRD / Factur-X invoicesPRO

To attach an electronic invoice, the value at type must be exactly the string ZUGFeRD invoice:

<AttachFile description="Electronic invoice"
            type="ZUGFeRD invoice"
            filename="invoice.pdf" />

The output filename is set to factur-x.xml for ZUGFeRD version 2 and ZUGFeRD-invoice.xml for version 1.

The PDF output must be set to PDF/A-3:

<PDFOptions format="PDF/A-3" />

This happens automatically if the command <AttachFile> is executed at the beginning of the document (before the first page output).

For a PDF document to be compliant with PDF/A-3, the colors must match the color profiles. In the PDF/A-3 default setting, an OutputIntent is defined for a CMYK color profile. Accordingly, the colors in the document must be defined in this color space. Or another color profile must be embedded.
attachfile zugferd
The file name is set to factur-x.xml for ZUGFeRD / factur-x version 2.