How are the PDF files named when downloaded? The name of the PDF files has the following structure: Date of receipt in the format year, month, day (YYYYMMDD) Sender (e.g. CAYA) Complete subject line Document ID (25 digits) Related articles Where can I find the document ID? How can I cancel CAYA? How can I share documents? How does the digitization of mail work? What happens to TAN letters, bank and credit cards?