Agree on the process early
Before work begins, ask who receives invoices, which reference they need, and how they prefer to pay. Use the due date agreed with the client.
Bill at the agreed milestone
Issue the invoice when you reach the billing milestone. Reference the project and explain the charge in ordinary language. Make any installment boundaries clear.
Send it to the right person
Attach the PDF and use a subject such as “Invoice INV-0042 — May design services.” In the message include the total, due date, and who to contact for corrections.
Reconcile after payment
Record the received payment against the invoice number. If only part of the amount arrives, record the date and the amount and reconcile the open balance in your bookkeeping system.