PRACTICAL INVOICE GUIDES

Invoice held up by a missing purchase order: what to ask

By Evrani · Published 1 November 2026

A client says accounts cannot process your invoice without a purchase-order reference. Another overdue reminder will not supply the missing information. First establish what their team needs, who can provide it and how to keep the original invoice traceable. This guide covers that administrative conversation, not a decision about contractual payment obligations.

Find out what is actually missing

The reference may already exist but have been omitted, the project contact may need to request one, or accounts may require a different submission channel. Ask which applies before changing the document. Use your established client contact or accounts thread.

An unfamiliar instruction to use a new portal or change sensitive payment details deserves a separate check through a known contact. Do not treat a forwarded email as authority to change those details.

Identify the invoice number and service period.
Ask whether a PO already exists and who owns the next action.
Confirm whether accounts needs the reference in the email, on the invoice or in an established portal.
Ask what acknowledgement to expect after submission.

Ask for the reference and an action owner

Keep the request narrow. If the recipient cannot provide the reference, ask them to route the request internally rather than guessing a colleague’s email. Ask for a date for an update, rather than assuming the invoice can now be paid.

Subject: Invoice [reference] — purchase-order reference needed

Hello [name],

Thank you for explaining that invoice [reference] for [service period] is waiting for a purchase-order reference.

Does a PO already exist for this work? If so, please confirm the reference and how accounts needs it supplied. If it still needs to be raised, who is arranging that and when should we check back?

Please also confirm the established submission route so we can keep one clear invoice record.

Thank you,
[business name]

Keep the original invoice traceable

Do not invent a PO number, silently change the original dates or create a second invoice merely to make the follow-up look new. Ask the person responsible for invoicing how an authorised correction should be recorded.

If your invoicing process issues a revised copy, identify the revision and retain the history. Confirm which copy the client should process. A conversation about missing administration does not by itself establish a new due date. Refer a disagreement about terms to the responsible person rather than a generic reminder.

Replace “waiting for PO” with a specific next step

A useful note names the blocker, action owner and next review date. “Waiting for client” hides whether they owe you a reference or your own team still needs to submit something.

Fictional example: SAMPLE-214 covers October design work. On 1 November the project contact says a PO is required. The note reads: “Client project team to confirm PO by 3 November; our invoicing owner then checks the document and submits through the existing accounts channel.” These are example review dates, not recommended payment deadlines.

Pause a generic chase while the specific query is handled.
Record when and where the information was submitted and any acknowledgement.
Ask whether anything else is missing and when accounts can provide a payment update.
If the agreed update does not arrive, follow up on that action.

Leave a useful handover note if someone else takes over

Use the pilot without replacing your invoicing process

Evrani supports holding an invoice for review while a query is handled. It does not generate a client’s purchase order or establish that an invoice has been approved for payment. Keep authorised documents and submission evidence in your established systems.

Evrani is an early-access development pilot using sample data while real-data legal arrangements are completed. Billing is disabled. Explore this workflow with fictional invoice details; do not upload real client personal data or confidential purchase orders.