If goods are insured by a seller (e. g. under CIF sale terms), and are damaged in transit, how is it possible for a claim to be made on the insurance?

When the shipping and insurance documents are passed to the buyer, the risk (of loss or damage) is transferred to him. 

The policy is said to be assigned to the buyer, enabling him to make a claim on it. The buyer can ascertain the place where claims are to be made from the Certificate of Insurance. On a Lloyd’s policy, for example, claims may be payable by Lloyd’s Agent at the discharge port.