An additional insured (sometimes called an additional interest) is a person, business or organization besides yourself who is protected by your car insurance policy and receives notifications and updates from your insurance company. They will receive a copy of the declarations page and any status forms. They will be notified if you cancel your coverage or change coverage levels.
Usually you add an additional insured to your insurance policy because:
Your car is financed or leased. Your lender or leasing company is the legal owner of your car and the loss payee on your car insurance policy. By adding the leasing company or lender as an additional insured, you protect it with your own policy if it is named in a lawsuit for an accident that you cause. Your lender will want to make sure that you have comprehensive and collision coverage that insures the value of the car, which is collateral for your loan. It also may require certain coverage levels or maximum deductibles.
You regularly use your car for business. If you use your own car to make sales calls, for example, your employer will want to make sure it is protected if you cause an accident on the way to an appointment.