1 · Confirm which system you invoice through
Federal agencies do not take invoices by email. The Department of Defense uses PIEE, the Procurement Integrated Enterprise Environment, which now also handles the invoicing function older contract documents may still refer to as WAWF. Civilian agencies commonly use the Invoice Processing Platform or an agency-specific portal. Your award notice or kickoff conference should say which one applies; if it does not, ask your contracting officer before your first invoice is due, not after.
2 · Get registered and linked to your contract early
Each system requires its own account setup, and linking that account to your specific contract number can take days. Do this in your first week of performance, not the week you are ready to bill. A correct invoice sitting in an unlinked account is functionally the same as no invoice at all.
3 · Build a proper invoice
A proper invoice under the Prompt Payment Act includes, at minimum, your contract number, invoice number and date, a description of what was delivered or performed, the period covered, the amount due, and your banking and remittance information on file. Match every line to the contract's billing instructions exactly, including whatever line-item structure it specifies. A close match is not the same as an exact match, and systems reject on formatting more often than people expect.
4 · Know what starts the clock
The Prompt Payment Act generally expects payment within about 30 days of a proper invoice being received, and interest accrues automatically when the government pays late on a proper invoice. The clock protects you, but it only starts once your invoice is actually proper and actually received, so keep your own submission records.
5 · Watch for the common holds
Most payment delays trace back to one of a few things: the government has not recorded formal acceptance of the deliverable yet, a receiving report was never filed on the government's side, a billing code does not match what the contract specifies, or the invoice landed in the wrong system entirely. When a payment runs past the expected window, check acceptance status first.
6 · Know who to nudge, and when
Your COR usually confirms whether the deliverable was accepted and a receiving report filed, since that is the technical side of the hold. Your contracting officer or the paying office handles the financial side once acceptance is recorded. A polite status check after 30 days is normal business, not a complaint, and it is far more effective than waiting silently.