How does auto insurance work?

I want to (finally) get my driver’s license. I do not own a car. I know that having some sort of insurance is usually mandatory, but I’m not sure what kind I need, if any, since I don’t own a vehicle. Most of the time I would be driving my boyfriend’s car (he does have insurance on it) and occasionally my parents’ cars (they have insurance too.) Do I need to be added to someone’s account or something? Or is it okay as long as all the cars I drive have insurance? I’d really like to avoid being added to an account if at all possible, because I don’t want to make someone’s payments go up.

I currently live in Missouri and North Carolina and could get my license in either state.

Thanks.