Changing child’s password
How do I change my child’s Apple ID password from my phone
How do I change my child’s Apple ID password from my phone
You can do it on the web site. See the last part of the first link.
What to do after you change your Apple ID or password - Apple Support I suggest doing this on the child's device before you change their Apple ID or password.
You can do it on the web site. See the last part of the first link.
What to do after you change your Apple ID or password - Apple Support I suggest doing this on the child's device before you change their Apple ID or password.
Changing child’s password