Shipper

As the party who contracts for carriage, the party who enters in a contract of carriage with a carrier and pays the carrier is in a position to give the carrier handling instructions. For freight-prepaid shipments this would usually be the seller, for freight-collect shipments, it would usually be the buyer.
As the party who delivers goods to carrier, the party who hands over cargo for transport is called “shipper”. However, in case of conflicting instructions, those given to the carrier by the counterparty may prevail when it is the counterparty who contracts for carriage.

Dictionary of International Trade