You can include someone else as a named driver on your car insurance policy, which covers them to drive your car. This will give them the same level of cover as the policy holder. As the policy holder, you must contact your insurer to add another person to your insurance as a named driver.
It’s worth noting that you should only ever include a named driver on your policy if they are not the main driver of your car. If you are the main driver but get someone else to claim that they are, this is called fronting and is not allowed. For example, if a young person were to put their parent down as the main driver in order to get a cheaper premium, then their policy could be cancelled and they could be prosecuted for fraud.