Invoice. According to Sohu News, merchants need to provide formal sales invoices for goods or services sold to consumers. This includes purchasing daily consumer goods, bulky goods and other services. Invoice helps to ensure the legality of the transaction and provides the buyer with a voucher to record the purchase. At the same time, the inclusion of invoices in accounting records is also an important link in business tax declaration and financial management. So under normal circumstances, the purchase of goods will be invoiced.