I can’t turn the find my iPhone off, so I can upgrade my iPhone

● If an app or feature on your device is not working, not appearing, or is restricted (grayed out), a frequent reason is it may have been disabled using Screen Time, or by an IT administrator if you are using a device owned by an employer or educational institution.

- Read this support article If your Apple ID or other options are greyed out in Settings —> If your Apple ID is greyed out in Settings - Apple Support

Tap Settings > Screen Time > Content & Privacy > scroll to Allow Changes and turn on.

- If the device is managed (Settings > General > VPN & Device Management), contact the IT department that is doing the managing.

● Situation where a VPN was preventing action —> Unable to sign out of my Apple ID on my i… - Apple Community

● Situation in which Terms And Conditions in Settings had not been agreed and was blocking access to certain features including automatic backups. —> My icloud and find my iphone are greyed o… - Apple Community

I had a problem with not being able to turn off find my iPhone. After phoning Apple, I was told to access Face ID & Passcode. Scroll down to Stolen Device Protection and toggle it to off. Problem solved. Thank you Apple!

This worked for me too. Thank you.

Huh. If I remember correctly I don't think that feature was even around when I posted my last reply to this question. :-/