An invoice approval workflow is the set of steps by which an organisation verifies a supplier's invoice and authorises it for payment. After the invoice is received and its data captured, accounts payable checks it against the order and delivery records through invoice matching. Invoices that match within tolerance may be approved automatically. Those without a purchase order, or with differences, are routed to the budget holder or the person who ordered the goods, and then, depending on value, to more senior approvers under a schedule of delegated authority.
The workflow is a key payment control. It enforces segregation of duties, since the person who approves an invoice should not be able to create the supplier or release the payment, and it leaves an audit trail of who approved what and when. Automated systems send reminders, escalate overdue approvals and hold a disputed invoice until resolved.