The consignor is the party that orders the carriage and hands over the cargo. Usually it is the seller, but it may be a forwarder acting on the seller’s behalf. Under the CMR it answers for the accuracy of the data it supplies for the consignment note and for damage caused by defective packaging.
In practice the consignor decides many things that later weigh on a claim: how the goods are loaded, what value is declared, which instructions are written. A forwarder issuing the consignment note on the customer’s behalf should go through them together.