Answer
The vendor master file is the central record of each supplier: legal name, addresses, contacts, tax IDs, bank/remittance details, payment terms, currency, and status. Accurate vendor master data underpins correct payments, tax reporting, and duplicate/fraud prevention, so changes to it are tightly controlled.
Real-world example Before a supplier can be paid, AP sets up a complete, verified vendor master record with validated bank details and tax ID.