Separating Child Apple ID from parent account

My understanding is it should automatically transition once the child turns 13 (or whatever age is used where you live). Try having him sign out and sign in again.

If you still have problems:

Contact Apple. Click here --> https://support.apple.com/choose-country-region Select your country, then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service --> "See a list of Apple phone numbers around the world."

Click here --> https://support.apple.com/HT201232

Some confusing statements here. If the child has an ID already that is "linked" (I don't know what you mean by that) to your account then why does the child need his own ID if he already has one? The only way a child's account could be linked to yours is with Family Sharing. There's an age requirement for that but if the child is old enough to have their own Apple account then the child is also old enough for you to now have to use family Sharing.

Create an Apple ID for your child - Apple Support

Have you checked Settings/Screen Time for any restrictions?

This is my question also. On my child’s phone you can’t sign out of it because the Apple ID button is not accessible on the child’s phone. Even when I deleted off family sharing, I couldn’t access their Apple ID. Help please.