An invoice or bill is a commercial document issued by a seller to a buyer. This document indicates the products, services, quantities, and prices the seller has provided to the buyer. An invoice indicates the sale transaction only.

A typical invoice contains following items:

• The word invoice
• A unique reference number
• Date of the invoice
• Credit terms
• Tax payments if relevant (GST/VAT)
• Name and contact details of the seller
• Tax or company registration details of seller
• Name and contact details of the buyer
• Date that the product/service was sent or delivered
• PO (purchase order) number
• Description of the product(s) or service(s)
• Unit price(s) of the product(s) (if applicable)
• Total amount charged
• Payment terms (method of payment, date of payment, late payment fess)

In situations where wire or electronic transfer is the preferred method of the payment, the printed bill will contain the bank account number and information and usually a reference code to be passed along the transaction identifying the payment.