Usually the interested party is the owner of the insured item, but others can qualify as well. If you finance a car, for example, the insurance agency considers the lienholder to be an interested party. A parent, guardian or loan co-signer also might qualify as an interested party.
No Interest? Not Interested
Insurance companies normally don't issue policies to anyone who isn't an interested party. If you buy a car and are unable to pay for the insurance, for example, you probably won't be able to convince your insurance company to allow a friend to insure the car instead if his name is not on the title. Even if it does, the friend might have a tough time filing a claim successfully if it's damaged. The company can argue that he didn't suffer any financial loss, since the car doesn't belong to him.