Invoice is time-stamped commercial document that itemizes and records a transaction between a buyer and a seller. If products or services were acquired on credit, the invoice would generally detail the conditions of the agreement and the various payment options available. If there is a billing problem, an invoice usually includes contact information for the seller or service provider. The payment terms and any discounts, early payment details, or finance costs levied for late payments may be listed on the invoice. The document also shows the entity's unit cost, the total number of units purchased, freight, handling, and shipping costs, as well as the total amount owed.