What AP Checks Before Approving Your Invoice

Your invoice is sitting in an AP queue. It is technically "received" but nothing is moving, and you are not sure why. Most of the time it is one of a handful of predictable problems, and every one of them is fixable before you send. Here are the questions people actually ask about AP approval, answered directly.

What does accounts payable actually check first?

The matching. Before an AP clerk looks at your line items or your bank details, they try to tie your invoice to something already in their system: a purchase order, an approved requisition, or a signed contract. If your invoice references a PO number, they pull that PO and compare the amount, the quantity, and the vendor name. This is the two-way or three-way match, and it is the single biggest gate.

If there is no PO number and their process requires one, the match fails at step one. The invoice does not get rejected with an explanation. It just stalls. That is why a missing PO number quietly kills an invoice more often than any other single field. Ask your contact whether a PO is required before you invoice, not after.

Which fields get an invoice rejected the fastest?

A short list does most of the damage:

• Wrong billing entity. You invoiced "Acme Inc" but AP pays for "Acme Global Services LLC." Different legal entity, no match, no payment.
• Missing or wrong PO number. Covered above. If their process needs one, nothing happens without it.
• Amount that does not match the PO. Your invoice is 4,200 dollars, the PO authorized 4,000. AP cannot pay the extra 200 without a new approval.
• No invoice number, or a duplicate one. AP systems reject duplicate invoice numbers as suspected double-billing.
• Missing tax details. No VAT number, no tax breakdown, or a tax rate that looks wrong for the jurisdiction.

The full field-by-field version is in our accounts payable invoice approval checklist, which you can run against any invoice before you send it.

How do I get the PO number and billing entity right?

The problem is that you often do not have this information when you build the invoice. You know your client as a person and a company name. AP knows them as a legal entity with a specific registered address and a PO you have never seen.

The usual fix is a back-and-forth: you send a PDF, AP emails corrections, you edit and resend, and you burn a week. A better approach is to let the recipient supply those fields directly. On a tool that lets the recipient edit their own invoice, they add the PO number, correct the billing entity, and set the billing address themselves. You get notified, and you can revert anything that looks wrong. No new version, no resend. If you have never dealt with a PO before, our plain explanation of purchase orders covers what the number is and why AP guards it.

Who inside AP actually approves it, and how do I reach them?

Usually two people. A clerk validates the invoice against the PO and enters it. A budget owner or manager approves the spend. The person who hired you is often neither. Sending your invoice to your day-to-day contact and assuming it reaches AP is where a lot of invoices disappear.

Get the AP email or the vendor portal instructions up front. If your invoice link supports it, set an AP contact and forward the invoice to them directly so it lands where approval happens. The mechanics of that hand-off are in our guide on getting an invoice to AP without it vanishing.

What happens if AP wants a change to the amount or terms?

This is different from a billing correction. If AP disputes a line item, a discount, or your payment terms, that changes the money on the invoice and needs your approval, not just theirs. On a static PDF this means issuing a corrected file and hoping everyone works from the right one.

A cleaner setup treats it as a tracked request. The recipient submits the change, you approve or decline, and an accepted change creates a new version (V2) with a full trail of what moved. PO and billing edits stay as amendments to the current version. If you want the distinction spelled out, see the practical difference between versions and amendments. Once a version is approved, it locks permanently, so the approved amount is the amount that stands.

How do I know my invoice was received and not lost?

You do not, if you emailed a PDF and heard nothing. "No reply" could mean it is in the approval queue, or it could mean it went to spam, or the wrong person is sitting on it. Before you chase, it helps to confirm the invoice was actually opened so your follow-up is aimed at the real problem.

Tracking the invoice through its statuses also tells you where it stalled. Sent, Viewed, Change Requested, Approved. If it went to Viewed and stopped, someone opened it and moved on. That is a follow-up you can time instead of guess.

What is the fastest way to pass AP on the first try?

Ask three questions before you invoice: Do you need a PO number? What is the exact legal entity and billing address? Where does the invoice go for approval? Put the answers on the invoice, match the amount to whatever PO they give you, use a unique invoice number, and include your tax details in full.

Then send it as a link rather than an attachment, so the recipient can fix their own PO and billing fields without a single resend. You can build an invoice like that in a few minutes, and it is free to send. Get those inputs right and the AP match happens on the first pass, which is the whole point.