It depends on your unique situation and the laws within your state, but there is usually a 30-day grace period before you would need to have proper registration. Because the vehicle would still need to be insured, you’ll want to make sure that you maintain active coverage. If you’re listed on the insurance policy, you could continue driving their car if you are on the policy — and it hasn’t been canceled — while you go through the process of updating the policy under your name or securing new coverage. It might be best to reach out to your insurance company or agent to learn what options are available to you.