OnePlus
Show or Hide the Lockdown Option in the Power Menu auf OnePlus
The Lockdown entry in the power off menu is not visible by default on most OnePlus phones. It only shows up once you switch on a dedicated toggle inside the security settings.
Once active, tapping Lockdown from the power menu forces the phone straight to PIN, password or pattern entry. Face Unlock, Fingerprint Scan and any Smart Lock trusted places or devices get suspended until you unlock manually with your credentials again.
This is useful before handing your phone to someone else, crossing a border, or whenever you want to rule out biometric or automatic unlocking for a short time. It is not meant as a permanent security mode, only as a quick way to drop back to credential-only unlocking.
To show or hide the option, open Settings ➔ Security & lock screen, then open the extra settings inside that page and enable or disable Show lockdown option.
If you cannot find the toggle, check that a screen lock method (PIN, password or pattern) is already set up, since Lockdown depends on having one active.