An invoice is a document listing billed goods and/or services that a provider presents to a customer.
Invoices provide customers with the amount of the total billing and itemize the details that make up the final charge. Charges listed on an invoice might include any taxes, stocking, shipping and handling fees and any additional charges on top of the initial requested goods or services. Invoices also list the quantities of individual items and their prices and often a description. An invoice number must be a unique identifier (UID) within a given system.
Most often, invoices are for services rendered or goods delivered. Even in the event of advance billing, invoices generally represent the final charges and any negotiation is likely to be prior to order confirmation, except in cases of error. Invoices serve both as a demand for payment by the party offering the good or service and a record of a fulfilled contract when paid in full by the requesting party.
Increasingly, invoices are created and submitted online; processes involved may be automated through e-invoicing software.