Most of the time your car insurance policy will cover anyone who drives your car with permission. Standard people who are covered include you, your spouse, and other household members. The car is insured, not the people who are driving it. As long as your car is insured, any driver in a legal age range is usually covered by your insurance.
The United States and Canada are the areas where car insurance is effective.

You can be denied car insurance if you have allowed someone to drive your car who was not legally allowed to drive it. This person might have been a minor or someone who had a suspended license. If you knew the person was not allowed to drive and allowed them to drive, you can be denied coverage.

There are a few other special circumstances. Check with the insurance company you are interested in purchasing a policy from to find out more information about their denial policies.