See attached sample: ZUGFeRD_2.3.3_Sample.Zip (3.0 MB)
it loads a file “Invoice.pdf” and adds “factur-x.xml” and stores it as “Invoice_ZUGFeRD.pdf” , following the guide at Creating PDF/3-A compliant PDF and attaching Z…...zip (3.0 MB) it loads a file “Invoice...“Invoice_ZUGFeRD.pdf” (also included in zip) fails to validate at https://portal3...