How can I add a child’s phone to my account
My child has an iPhone 7. How do I add the phone to my Apple ID account?
iPhone 7
Apple’s Worldwide Developers Conference to kick off June 10 at 10 a.m. PDT with Keynote address
The Keynote will be available to stream on apple.com, the Apple Developer app, the Apple TV app, and the Apple YouTube channel. On-demand playback will be available after the conclusion of the stream.
The Keynote will be available to stream on apple.com, the Apple Developer app, the Apple TV app, and the Apple YouTube channel. On-demand playback will be available after the conclusion of the stream.
My child has an iPhone 7. How do I add the phone to my Apple ID account?
iPhone 7
I would recommend that your child get his or her own Apple ID. If you just log in with your Apple ID, then your child will also receive your messages, photos, etc.
Once your child has their own Apple ID, you can use Family Sharing. Then you have 100% control over which apps your child downloads, screen time, etc.
Here you can see how to set up Family Sharing
https://support.apple.com/kb/HT201088
If your child does not have an Apple ID:
I would recommend that your child get his or her own Apple ID. If you just log in with your Apple ID, then your child will also receive your messages, photos, etc.
Once your child has their own Apple ID, you can use Family Sharing. Then you have 100% control over which apps your child downloads, screen time, etc.
Here you can see how to set up Family Sharing
https://support.apple.com/kb/HT201088
If your child does not have an Apple ID:
I agree with the above.
To try to answer your question, use the article below as a guide to places where you need to sign into the child's phone to add the phone to your ID.
What to do after you change your Apple ID or password - Apple Support.
How can I add a child’s phone to my account