Created accidental child account
I created a child account but it told me it was already taken. Then it was still added to our family sharing. How do I delete?
iPhone 7, iOS 12
See if the below works.
Make sure you sign out from the places in the 4th link before deleting the ID.
How to delete your Apple ID account
What to do after you change your Apple ID or password - Apple Support
If necessary, contact Apple ID Support.
Apple Support by e-mail or chat Work through the screens to get a chat option.
Or fill out and submit this form. The form is for iTunes, but it will get passed to the ID Support section.