
If you sell to government bodies (or get paid through government reimbursement schemes), you can do everything right operationally and still get paid late for one simple reason: you can't prove acceptance in the way the payor's process recognizes.
A lot of teams treat acceptance as the same thing as proof of delivery. It isn't. Proof of delivery answers: "Did it arrive / did the work happen?"
Acceptance evidence answers: "Did the authorized person confirm it met the requirement, in the required format, with the required references?"
Government payors often run payment through validation gates. If acceptance isn't clearly evidenced—or can't be found quickly—your invoice doesn't necessarily get rejected. It just gets parked. And "parked" is where forecasts go to die.
This guide explains what strong acceptance evidence looks like for both goods and services, with concrete examples and a copy/paste checklist you can implement internally.
Acceptance evidence is any document, system record, or written confirmation that shows:
For goods, acceptance is usually tied to receipt and inspection. The exact workflow varies, but strong evidence tends to fall into a few recognizable categories.
Often the simplest and most common. Strong delivery notes include:
Some payors generate a receiving record that confirms goods were receipted into their system. This can be very strong because it's system-native.
Many government bodies use portals or internal systems where the status changes to "received," "accepted," or equivalent. Screenshots can be valid evidence if they show:
An email can be strong acceptance evidence if it is:

Think of "good" evidence as evidence that:
"Bad" evidence is usually evidence that is technically a delivery record but fails the validator test:
A delivery note listing item codes and quantities, signed by [Name], role [Receiving Officer / Warehouse Supervisor], dated [DD/MM/YYYY], with PO [12345] clearly printed at the top and line quantities matching the PO.
A system-generated goods received note showing PO [12345], receipt date [DD/MM/YYYY], received quantities by line item, and the receiving location. The GRN number is visible and can be referenced on the invoice.
A screenshot from the payor portal showing the order reference, the delivery line, status "Received," and a timestamp/date. The screenshot file name includes invoice and PO reference for easy retrieval.
An email from [Authorized Approver Name] stating: "Confirmed receipt of [items] under PO [12345] delivered on [date]. Goods received in good condition." The email is saved as a PDF and stored in the invoice's clean file folder.
Services are harder because "delivery" is not always a physical event. Acceptance can depend on quality, completion, milestones, and whether work meets a defined scope. That means service acceptance evidence must be more explicit. If it's ambiguous, it becomes disputable.

Strong timesheets include:
For milestone-based work, the cleanest evidence is a short sign-off document that states:
A short completion/performance report (even one page) endorsed by the client can be excellent evidence if it ties clearly to scope and period.
Email acceptance is common and can be strong if it's precise:
A timesheet covering [01–31 Month], listing hours by day, tagged to Contract [ABC] / Call-off [001], approved by [Name], role [Project Lead / Service Manager], dated [DD/MM/YYYY].
A one-page sign-off stating: "Milestone 2 complete: [deliverable description]. Accepted on [date] under Call-off [001] against Contract [ABC]." Signed by the designated approver with role/title.
A short report summarizing activities and outputs for the period, with a client endorsement line: "Reviewed and accepted," signed/dated, referencing the service period and call-off/PO.
An email from the designated approver: "Confirm acceptance of services delivered for period [dates] under PO [12345]. No issues noted." Saved and filed in the invoice pack with a clear file name.
Acceptance is only as strong as the authority behind it. When invoices get queried, a common failure mode is: "Yes, we have a signature… but it's from someone who isn't recognized as an approver."

Identify the authorized approver roles per payor/program (not just a person's name).
Capture acceptance from the role that can actually confirm receipt/performance and unlock approval.
If acceptance can be recorded in a portal/system, prioritize that evidence because it's typically harder to challenge.
Use this as a practical gate before invoicing or when responding to a query.
Before we invoice (or before we chase payment), we have:
Before we invoice (or before we chase payment), we have:
The evidence would make sense to someone outside the project team
The evidence ties cleanly to the exact invoice line items/period
If questioned, we can respond in minutes with labelled files (not a document dump)
If you standardize acceptance evidence, three things happen fast:

Government Invoice Acceptance Evidence: What "Good" Looks Like for Goods and Services