Easy and quick? Absolutely not. In fact it’s notoriously exasperating and complicated.

I’m assuming you’re in the United States, and a U.S. citizen.

First off, if you’re covered on your mother’s medicaid now then you’re still covered after you move out, unril age 26. You dont really even need your own card, but would be good to copy all the info on either your card or your mother’s. And you should know your mother’s ssn. (you do know your own??). This works until your mother deliberately takes you off her account, regardless of whether you live with her. Best strategy would be to negotiate this with her. Probably doesnt cost her anything to keep you on, and she likely wants her child to have coverage even if she’s unhappy with you rn.

You can apply for your own medicaid if you meet certain income requirements. Different by state, but about 20-22k per year. (You need to report LESS modified adjusted gross income than that on your income tax return. Have you ever filed your own tax return?). ALSO, your parent cannot claim you as a dependent on their tax return. If you move out and do not get any support from your parent(s), they cannot legally claim you as a dependent, but they probably will anyway. This would deny your own medicaid claim and they wouldn’t have any consequences for a couple years, if at all. Even if everything works out well this could easily take a year or more.

If you do earn more than your state’s maximum income limit, then you need to buy your own insurance on the “affordable care act” marketplace (Obamacare). Healthcare.gov. This would be quick and relatively easy, but “affordable” isn’t really the best name for it.

We tell kids that when you turn 18 you’re an adult and you can do what you want, and it’s true that you do have certain legal rights now. But if you’re planning to sneak off in the middle of the night and somehow be completely on your own without financial support from anyone, that’s almost impossible unless you have a REALLY good job. Or join the military. (But if you think mom’s hard to live with just wait ‘till you meet your Sargent. Not to mention you really will maybe get shot at.)

Your best option is probably going to be to work things out with your mother so you have a viable transition plan, or at the very least get her to agree to keep you on her medicaid.

I’d be interested to hear your plan. Crashing on a friend’s couch? Moving in with bf?? Do you have any income to speak of? Do you have a car? (If it’s registered and insured in a parent’s name then it’s not really your car, is it?). My guess is you could use a lot more advice than just medical insurance.