A readable PDF copy, for everyone who needs paper logic
The XML is the invoice; this tool gives it a human face. Approval rounds, project folders and managers all want something readable, and a rendered PDF of the XRechnung serves exactly that purpose in seconds, with the parties, line items and totals laid out like a classic invoice.
One rule keeps you compliant: the copy is for reading, never for the records. Retention law wants the original file, unaltered and machine-readable, so archive the XML itself and attach the PDF copy wherever people need it.