The term endorsement used in the endorsement of insurance clauses refers to the modifying of insurance to include risks not covered in the basic policies by adding suitable clauses and paying additional premium. For example, in the Institute Cargo Clauses none of the three basic policies covers the risks of war, strikes, riots, and civil commotions. In order to cover against such risks, the F.C.&S. Clause (Free of Capture and Seizure Clause) and the F.S.R.&C.C. Clause (Free of Strikes, Riots and Civil Commotions Clause) are deleted from the policy (by stamping the word "DELETED" over such clauses usually) and the Institute War Clauses and the Institute Strike Clauses are endorsed.

The endorsement usually is in the form of pre-printed clauses attached (i.e., stapled, gummed or taped) to the policy. Some policy forms may be provided with an endorsement space wherein the clauses are typed and/or attached.

There are clauses which are approved by certain associations (e.g. bank, trade, etc.) to suit the particular market needs. For example, the Bank Clause:

"It is warranted and agreed to by the Assured and the Company that in the event of loss or damage becoming recoverable under this Policy, the Company will not be liable for more than its share of the loss or damage at the rate of exchange mentioned in this Policy."

(The word "Company" above refers to the insurance company.)