Field help (VATBIS) 

Enter the VAT management type associated with the supplier invoice.
Only a tax rule with a legislation and group that are consistent with those of the document can be entered.
SEEREFERTTOThe general principles linked to the multi-legislation setup are detailed here.

This field is automatically entered if a tax rule is specified in the record of the supplier of the current invoice. This is used, among other things, to obtain a print conditioned by the type of legislation.