The bill of lading is a document prepared at the time of shipment of goods to a customer indicating the description of the merchandise,the quantity shipped, and other data. Formally, it is a written contract of the shipment and receipt of goods between the seller and carrier.It is also used as a signal to bill the client. The original is sent to the customer and one or more copies are retained. b. A sales invoice is a document indicating the description and quantity of goods sold, the price including freight, insurance, terms, and other relevant data. It is the method of indicating to the customer the amount owed for the sale and the due date of the payments. The original is sent to the customer and one or morecopies are retained. The sales invoice is the document for recording sales in the accounting records. c. The credit memo is a document indicating a reduction in the amount due from a customer because of returned goods or an allowance granted. It often takes the same general form as a sales invoice, but it reduces the customer’s accounts receivable balance rather than increasing it.