Can you drive someone else's car while doing Shipt?

Yes, you can drive someone else's car with Shipt. As long you are insured on the policy that covers the car.

You don't have to own the car you drive while shopping with Shipt.  However, you do have to be insured on the policy that covers that car. If you are not an insured driver on the policy for a car, you cannot use that car while working with Shipt.