Special Features of Posting Documents 
The system makes entries in the Ref. 1 and Description fields automatically for a journal entry that is created automatically using a business transaction, such as an invoice or a delivery. You can find the contents of these fields as Document Field 1 and Text in the DATEV export file.
For incoming or outgoing invoices in the journal that are created manually, we also recommend filling in both of these fields manually and using them as a reference. This makes it easier to trace individual postings in the DATEV export file.