What Is an Invoice? Definition, Types & Examples

An invoice is a dated, numbered commercial document that a seller sends to a buyer to request payment for goods or services delivered. It itemizes what was supplied, the price of each item, any taxes, the total due, and the payment terms. Invoices create the official paper trail for accounts receivable and tax records.

What an invoice contains

• Invoice number — a unique, sequential identifier.
• Issue date and due date.
• Seller details — business name, address, tax ID.
• Buyer details — name, company, billing address.
• Line items — description, quantity, unit price, line total.
• Subtotal, tax, grand total.
• Payment terms and payment instructions.

The main types of invoice

• Standard invoice — the default request for payment after delivery.
• Proforma invoice — a preliminary quote-like document sent before delivery (see what is a proforma invoice).
• Recurring invoice — issued on a schedule for subscriptions or retainers.
• Credit note — a negative invoice that reverses or reduces a prior charge.
• Commercial invoice — used for international shipments and customs clearance.

Worked example

A freelance designer sends INV-0042 dated June 15, 2026, billing "Acme Co." for 8 hours of UX work at $150/hour. The invoice shows a subtotal of $1,200, a 10% sales tax of $120, a grand total of $1,320, and "Net 14" payment terms with a Stripe payment link.

Invoice vs receipt

An invoice requests payment; a receipt confirms payment was received. Most transactions need both. See our invoice vs receipt guide for a full comparison.

Create an invoice in minutes

You don't need accounting software to send a professional invoice. Use the free ProeInvoice generator to build, brand, and download a PDF invoice — no signup. Or browse our invoice template library for industry-specific layouts.

Next steps

Ready to write your first one? Read how to write an invoice for a step-by-step walkthrough.

Frequently asked questions

What's an invoice in simple terms?

An invoice is a dated, numbered bill a seller sends to a buyer listing what was provided, the amount owed, and how to pay. It creates a legal record of the transaction.

Is an invoice the same as a bill?

"Bill" is the informal word a customer uses for the same document a seller calls an invoice. The document and its legal effect are identical.

Is an invoice a legal document?

Yes. Once issued, an invoice is a binding request for payment and a primary record for tax and accounting purposes in most jurisdictions.

What information must every invoice include?

A unique invoice number, issue date, seller and buyer details, an itemized list of goods or services, totals with applicable tax, payment terms, and payment instructions.