Account changes are restricted by a profile

If an app or feature on your device is not working, not appearing, or is restricted (grayed out), 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.

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

on iphone->settings->screen time->content and privacy restrictions.

go below and set "Account changes" to allow (this will allow on mac and other devices to be able to remove that restriction but signoff button is still grayed out )