On a supported iPhone, touch and hold the Messenger icon, tap Require Face ID, Require Touch ID, or Require Passcode, then authenticate. The control applies only to that iPhone and locks the whole Messenger app—not one conversation.
Set the lock in four steps
- Confirm that Face ID, Touch ID, or a device passcode is already set.
- On the Home Screen, touch and hold the Messenger icon.
- Choose the available Require… authentication option and confirm it.
- Leave Messenger, reopen it, and verify that iOS asks you to authenticate.
Locking and hiding are different
Locking leaves Messenger visible but requires authentication to open it. Hiding moves a downloaded app into the authenticated Hidden folder. Apple notes that a lock or hidden state is local to that iPhone and does not sync through iCloud.
If the menu is missing, confirm the iOS version and check whether device management or family settings limit the feature. Do not install a profile from an unknown website to imitate an app lock.
Undo the change safely
Touch and hold Messenger, choose Don’t Require Face ID (or the equivalent), and authenticate. Removing the gate does not delete conversations. If you hid the app, open the Hidden folder in App Library and authenticate before changing the setting.
