iPhone says you can’t sign out due to restrictions?

Open Settings and choose Screen Time. In Apple’s current menu, open Manage Screen Time, then Change Screen Time Passcode. If you manage these settings and know the passcode, choose Turn Off Screen Time Passcode and enter it. Return to Settings, open your name and check whether Sign Out is now available.

In Screen Time, open Content & Privacy Restrictions. Under the privacy controls, find Allow Changes to Settings and open Accounts. Select Allow and enter the Screen Time passcode if asked. Menu wording can vary with the system version. Check the account row again before changing any other restriction.

If a parent or guardian manages your Screen Time through Family Sharing, ask them to review the restriction. Apple directs changes to a child’s Screen Time passcode through the family organizer’s or parent or guardian’s device. If neither Screen Time setting explains the symptom, note which control is disabled and contact Apple Support.

Confirm recent iCloud changes are visible on iCloud.com or another device, and check that your backup is current. Sign-out affects iCloud and other services on that device. If you intend to keep using the device, read the prompt about what stays on it and choose the option to sign out without erasing it.