The record of a payment is the last piece of an invoice's history and the one most often left incomplete. Internally, the payment should be recorded against the invoices it settles rather than as an isolated bank transaction. Externally, the supplier should be told what it covered. Both are cheap, and skipping either creates work that arrives later as queries.
Internally: payment against invoice
Recording which invoices a transfer settled is what makes the payables record complete and what makes reconciliation possible. A payment recorded only as a bank line has to be allocated later by somebody working backwards from amounts, which is exactly the kind of reconstruction that produces errors and consumes month-end time.
Externally: the remittance advice
A short note listing the invoices covered, with numbers and amounts, plus any credits applied. Without it a supplier receiving one transfer for eleven invoices cannot allocate it and will guess or telephone. Sending it automatically as part of the payment run removes a category of query from both organisations at effectively zero cost.
What to retain
The payment record with its date and reference, attached to the invoices it settled, retained for as long as the invoices themselves. It is part of the record of the transaction, and it is what answers a supplier claiming non-payment months later. Retention periods depend on your own obligations and should be applied consistently.
Questions people ask about invoice payment receipt
Is a bank statement enough evidence?
It evidences the transfer but not what it settled. The allocation is what answers a supplier query, and it belongs on your record.
Should we send remittances for single invoices?
They matter most where one payment covers several invoices or where credits are applied. Sending them always is simpler than deciding case by case.
What if a supplier says they were not paid?
The payment record with its allocation and the remittance you sent answers it in a minute. Without them it becomes a reconstruction.