What Is an Invoice?
An invoice is a document a seller sends to a buyer that lists the goods or services provided, the amount owed, and the payment terms. It's the formal request for payment and the source document that creates an account receivable.
What an invoice is and why it matters
The invoice is where a sale on credit becomes a trackable obligation. A complete invoice includes an invoice number, date, the buyer and seller, an itemized description with quantities and prices, the total due, and payment terms (like Net 30). It triggers the receivable on the seller's books and the payable on the buyer's, and it's a key document in the audit trail. Prompt, accurate invoicing directly affects cash flow — delays in sending invoices push back collections and lengthen days sales outstanding.
A worked example
A web agency finishes a project and issues invoice #1050 dated April 5 for $8,000, itemized as 80 hours at $100/hour, with Net 30 terms (due May 5). On sending it, the agency records a receivable: debit *Accounts Receivable* $8,000, credit *Revenue* $8,000. The invoice number and date anchor the transaction in the records, and the due date drives collection follow-up if payment slips.
How firms handle it today
Firms generate invoices from the accounting or billing system, track them through the receivables ledger and aging report, and match incoming payments back to the original invoice at reconciliation.
How OCTA Flow relates to invoices
OCTA Flow can support the invoicing-to-collections workflow — helping generate and track invoices, match payments, and drive follow-up on overdue balances — with every step logged for review.
Related terms
- Accounts receivable
- Net 30
- Credit note
- Aging report
- Purchase order
FAQ
What should an invoice include?
An invoice number, date, buyer and seller details, itemized goods or services, the total due, and payment terms.
What's the difference between an invoice and a receipt?
An invoice requests payment before it's made; a receipt confirms payment after it's been received.
What's the difference between an invoice and a purchase order?
A buyer issues a purchase order to request goods; the seller issues an invoice to request payment for them.