Field help (BPRFCT) 

This information is initialized by default by the Factor code for the bill-to customer if it exists, but it remains modifiable.
The presence a Factor code in an invoice indicates that this invoice is transferred to a factoring organization and that the payment must be made in favor of the Factor (see the Factor documentation).
From this field, the user can directly enter a factor whose existence is controlled in the corresponding table or use the contextual button to: