Field help (SOQBPTNUM) 

This is the carrier used to transport the goods to the customer delivery address. It is managed in the Carriers table. This information is initialized with the carried entered in the order header but it can be modified on the line if the order delivery mode is not set to the value Ship order complete. If the delivery address is modified on the order line, the carrier is reassigned by the value mentioned on the delivery address.

The carrier is used later on the delivery note in order to calculate freight in accordance with the delivery weight and volume.