Verify child's Apple ID and password by going to https://www.icloud.com/ from a PC or MAC and logging in.
- Tap Settings on child’s phone.
- Tap iCloud.
- If phone is logged into the parents Apple ID Sign Out (if not next step).
- Tap Sign Out again to confirm.
- Choose Keep on My iPhone when you're asked what you want to do with your iCloud data.
- Enter your password to sign out.
- Enter child’s Apple ID and password
- Sign in.