A seller's duties under CIF contract are: (a) to make out an invoice of the goods sold, (b) to ship at the port of shipment goods of the description contained in the contract and (c) to prepare a contract of affreighment, under which the goods will be delivered.

A CIF (Cost, Insurance, Freight) contract requires the seller to perform three key duties: prepare an invoice for the goods, ship the correct goods at the port of shipment as specified in the contract, and arrange a contract of affreightment (shipping contract) to deliver the goods. These are indeed the seller's primary obligations under CIF terms, which place most responsibilities on the seller until goods reach the destination port.