Three kinds of agency revenue
Project fees, retainers and pass-through costs behave differently and should be separated on the invoice. A project fee is earned when the milestone is delivered; a retainer is usually billed in advance for a period; pass-through media is money you spent on the client’s behalf. Mixing them makes the invoice hard to reconcile and hides what the client is actually paying for.
Markup vs pass-through
If you mark up media, production or subcontractors, disclose the markup in the contract and apply it the same way every time. If you pass costs through at cost, attach the platform or vendor invoices. A client who cannot see the backup will assume the worst.
Retainers and scope
State the retainer period, what is included and how unused hours are treated — rolled over, forfeited or billed separately. Retainers that roll over indefinitely become a liability; set a cap in the contract.
Approvals and POs
Large clients often need a signed SOW or a purchase order before they can pay. Put the SOW or PO number on the invoice and send it to the person who actually approves, not just the day-to-day contact.
Getting paid
Agency invoices are among the largest a small business sends, so terms matter. Net 30 is standard; a deposit for project work is common. For the earlier pricing document, use the blank quote template; for late payment, the payment terms guide has a reminder sequence.