The third step in preparing for a shipment is to ensure all necessary documentation is in order. This includes a commercial invoice that lists the goods, seller/buyer information, terms of sale, and payment method. An air waybill serves as a contract of carriage between the shipper and carrier, and lists details such as origin, destination, weight, dimensions, and tracking number. A packing list should include the contents and quantity of each package in the shipment, as well as total weight and volume. Depending on the type and destination of goods, other documents may be required such as a bill of lading, certificate of analysis, health certificate, or export license. All documents should be accurate, complete, and consistent with enough copies for each party involved in the shipment.