Purchase order invoicing for agencies
A correct invoice can still stall when it lacks the client’s purchasing reference. Build the PO check into onboarding, keep a manual balance register and make the relationship to each invoice explicit.
Product claims checked against the ABH truth sheet on 14 October 2026. Examples are fictional and illustrative. Operational guidance only, not legal, tax or accounting advice.
Short answer
Obtain and validate the client PO before work where required, put its reference on applicable invoices and check each charge against the remaining authorization. ABH invoice notes can hold the reference; PO matching and procurement integrations are not available.
Review current plans for the time and invoicing workflow. Client funds are received outside ABH and recorded manually.
What a purchase order is and when clients require one
A purchase order is a client's purchasing reference and authorization record. Some clients require an approved PO before accounts payable can accept an invoice. Ask what their process requires rather than assuming every engagement uses one. Identify the buyer, billing entity, approved scope, amount, currency and period, and confirm who can authorize a change when work exceeds the original order.
A PO process can be separate from the person who approves creative work. The delivery contact may be happy with a milestone while procurement still needs a valid reference. Treat these as distinct checks. ABH does not integrate with procurement or accounts payable systems. Your team must obtain, review and retain the client's order through the client's own process.
Get the PO before work starts
Request the approved order before allocating delivery work, where the client's rules require it. Check that the supplier name matches your agency and that the document covers the agreed service. Clarify whether the value includes taxes and expenses. A draft reference in an email may not be the approved order that the client needs for invoice matching. Assign a person to confirm readiness.
Add the PO requirement to client onboarding billing setup, including the accounts payable contact and submission method. ABH offers proposals and e-sign contracts on Starter and Pro, but those documents do not replace a client's purchasing authorization. If the order has not arrived, agree the next step explicitly rather than silently assuming that an accepted proposal satisfies procurement.
Put the PO number on every invoice
Copy the exact reference onto each applicable invoice, preserving meaningful letters and leading zeros. Confirm whether the client needs a service period, buyer name or supplier code beside it. Review a draft with the billing contact if their format is unfamiliar. Keep the invoice number distinct from the PO number: one identifies your document, the other identifies the client's purchasing authorization.
ABH has client-visible invoice notes that can hold a PO reference. It does not have a dedicated PO field or procurement matching integration. Use clear wording such as “Client purchase order: PO-0048” in those notes, then inspect the invoice output before sending. The invoice numbering guide explains why the agency's own sequence must remain separate.
Match invoice amounts to the PO balance
Maintain a manual order register showing approved value, prior invoices, pending invoices and remaining authorization. Compare amounts on the same tax and currency basis. An invoice below the original order total can still exceed its remaining balance after earlier billing. Ask for an amended or additional order before billing work that is outside the current authorization. Do not assume a remaining balance authorizes unrelated services.
Illustrative fictional example, USD, excluding taxes: a PO authorizes $12,000, with $4,000 already invoiced and another $3,000 invoice awaiting submission. The unallocated balance is $5,000. A proposed $6,000 invoice needs investigation before issue. This is a manual control example, not an ABH PO balance calculation. The milestone invoicing guide helps align that register with delivery events.
Split invoices across multiple POs
When one engagement uses several POs, map each deliverable or billing period to the correct authorization. Ask whether the client wants separate invoices per PO or permits a documented allocation on one invoice. Do not spread the same charge across multiple orders merely to make the balances fit. Preserve the relationship between work, authorization and invoice in your register so another person can check it.
For a fictional split, one order could cover discovery while another covers implementation. Invoice each agreed milestone against its matching order and reconcile the totals back to the project fee. Review agency payment terms for the due date and submission agreement. The agency billing process places this purchasing check between accepted scope and invoice issue.
Record payments against the PO reference
When a remittance arrives, match the invoice reference as well as the PO. A client may use one order number for several invoices, so the PO alone may not tell you how to allocate the receipt. Ask for remittance detail when necessary. Keep partial receipts and unresolved allocations visible until the external payment evidence supports the bookkeeping entry.
ABH supports invoice due dates, statuses, PDFs and a public invoice link. An Owner records confirmed external payments manually in an append-only ledger with exact amounts; ABH collects no client money. Keep the PO register outside that payment record. The small agency overview describes the wider workflow, and currency invoicing guidance covers orders billed in a different currency.
Frequently asked questions
Does ABH have a dedicated purchase order field?
No dedicated PO field is available today. Client-visible invoice notes can hold the reference, which you should inspect before sending.
Can one PO cover several invoices?
The client may allow that arrangement. Maintain a manual running allocation and confirm the remaining authorization before each invoice.
Is the PO number my invoice number?
No. Preserve your own invoice sequence and show the client purchasing reference separately so both records can be reconciled.
Match each invoice to its authorization.
Review current plans for the time and invoicing workflow. Client funds are received outside ABH and recorded manually.