Want to get rid of a hacker on my iPhone

It's a scam. Ignore it.

A pop up said your phone has been hacked I was on go go a anime website and it gave me that pop up but I didn’t press close I didn’t close the pop up and I turn off my phone

That's the right thing to do.

In an abundance of caution (and to prevent the scam popup from reappearing), go to Settings > Safari > Clear History and Website Data.