Auto insurance is designed to follow the car, which means that the coverage you purchased for your vehicle will cover the car regardless of who’s driving it.
That said, in order to be fully covered by your insurance policy, the person driving your car must have permission (verbal or written) to do so.
The person driving your car must be an occasional driver only, not a regular driver or user of the vehicle. If they get into an accident while driving your car (and considering they had your permission to drive the car at the time of the accident), your auto insurance will be considered the primary coverage in any accident-related claim that’s made. The driver’s auto insurance coverage will be considered a secondary coverage, and will only activate if damage claims exceed the limits of your policy.