An invoice is a time-stamped commercial document that itemizes and records a transaction between a buyer and a seller. If goods or services were purchased on credit, the invoice usually specifies the terms of the deal and provides information on the available methods of payment. An invoice typically contains contact information for the seller or service provider in case there is an error relating to the billing. Payment terms may be outlined on the invoice, as well as the information relating to any discounts, early payment details or finance charges assessed for late payments. It also presents the unit cost of an item, total units purchased, freight, handling, shipping, and associated tax charges, and it outlines the total amount owed.