I made anew Apple ID a few days ago but And I want to change my current if on my phone to the new one I made but for some reason everyone I do; it says that my ID is being used by another account? How should I fix that?
iPhone 8, iOS 15
You should have changed your current Apple ID, rather than create a new one and then replace the current one with the new one.
See this Apple article: Change your Apple ID
Change your Apple ID - Apple Support (SG)
it says that my ID is being used by another account?
Yes, is use by your self.
FYI: you can't merge multiple Apple ID.
See this Apple article: Sign in with your Apple ID
Sign in with your Apple ID - Apple Support
👉 use one Apple ID to access all Apple services and make all of your devices work together seamlessly.
Login with Apple ID issue
