Files and supporting documents can be added to the invoice. They must be embedded in the invoice data file. The maximum size of an invoice depends on the transmission method (input channel) selected. Concerning this, please refer to the terms of use of the portal in question. Documents having the following file types may be embedded: “png”, “pdf”, “jpg”, “jpeg”, “xlsx”, “ods” and “csv”, as well as the file type “xml” if using the XRechnung extension. Attachments may not contain any active content such as macros.