Invoicing has its own vocabulary, and knowing it helps you sound — and operate — like a professional from day one.
Net 30 / Net 15 / Net 7
The number of days after the invoice date that payment is due. 'Net 30' means payment is due 30 days from issue.
Due on Receipt
Payment is expected immediately upon the client receiving the invoice, rather than after a set number of days.
PO Number
A purchase order number, often required by larger companies to match an invoice to an internally approved order before payment is processed.
Line item
An individual entry on the invoice describing a specific product, service, quantity, and price.
Subtotal
The total cost of all line items before tax or discounts are applied.
Credit note
A document issued to reduce or cancel all or part of a previously issued invoice, commonly used to correct errors or process refunds.
Recurring invoice
An invoice issued on a repeating schedule, typically for retainer or subscription-based work.
Aging report
A summary showing how long outstanding invoices have been unpaid, often grouped into ranges like 0-30, 31-60, and 60+ days overdue.
Why this vocabulary matters
Using these terms correctly — both in your invoices and in conversations with clients — signals that you run your freelance business with the same rigor as an established company.