A debit note is a commercial document used in business-to-business transactions to inform a seller of the amount of goods being returned or to request a credit note from the seller. It is a formal request for a credit note and acts as evidence for the occurrence of a reduction in expenses. Debit notes are generally used in business-to-business transactions that involve an extension of credit, meaning that a vendor would send a shipment of goods to a company before the goods have been paid for. Debit notes can be issued by either the buyer or the seller for various reasons, such as to remind the customer of a payment due for goods and services delivered or to adjust the amount of an invoice already issued. Debit notes are not the same as invoices, as they are used to show returns or adjustments made to an order, while invoices can be used to show a sale or a transaction.