To register a car, you typically need to provide proof of ownership, such as a title or registration document. If you are not the owner of the car, you will not be able to provide this documentation and will therefore not be able to register the vehicle.
Similarly, to insure a car, you typically need to be the owner of the vehicle or a named insured on the insurance policy. If you are not the owner of the car, you will not be able to obtain insurance for the vehicle.
However, there may be some exceptions to these general rules. For example, in some cases, you may be able to register and insure a car that is owned by a family member or close friend, even if you are not the legal owner of the vehicle. In such cases, you will typically need to provide written permission from the owner of the car and may also need to meet other specific requirements.
If you are unsure about whether you can register and insure a car that you are not the owner of, you should contact your local Department of Motor Vehicles (DMV) and your insurance company for specific information and guidance.