How do I regain control over my iPhone and Apple Account after turning 18?

I just turned 18 and got an email from apple stating that I would now have control over my phone and my apple id but my parents still have full control over my phone including my apple id and screen time and everything. Do I just need to wait a little or do I need to ask them? I would prefer not needing to ask them as I know they'll just tell me no and continue to heavily control my phone

[Re-Titled by Moderator]

Original Title: I'm 18 and my parents still have full control over my phone. What do I need to do?