Quick answer
Touch and hold an eligible app, choose Require Face ID, Touch ID or Passcode, and authenticate. The icon can remain visible while opening the app requires authentication.
Method
Device authentication
Steps
- Find the installed app on the Home Screen or in App Library.
- Touch and hold its icon and inspect the available actions.
- Choose Require Face ID, Touch ID or Passcode, then confirm the lock without selecting Hide.
- Close and reopen the app to verify the lock and understand the fallback offered by the device.
Limits
Not every app can be locked. Device authentication is not an independent password for each app, and the lock applies only to this device.
Find your app
| App | Installed type | What to check |
|---|---|---|
| Photos | built-in | Use the Hidden collection for pictures and videos; app visibility and photo-library access are separate controls. |
| Messages | built-in | Start with notification previews and the difference between a conversation and a saved attachment. A photo saved from a message can exist in Photos too. |
| Safari | built-in | Private browsing, browser history and application visibility answer different privacy questions. The built-in browser is not an eligible downloaded app for the Hidden folder workflow. |
| Notes | built-in | Distinguish locking an eligible application from protecting a specific note. The app-level menu does not establish the recovery rules for a locked note. |
| downloaded | For a separately downloaded installation, inspect the iOS icon menu for locking or hiding. Eligibility and family or device restrictions determine which options are available. | |
| downloaded | Inspect the iOS lock or hide menu for the installed app. Removing its Home Screen icon leaves the app installed and does not change access through the account elsewhere. |
Questions
How do you lock an app on iPhone?
Touch and hold an eligible app, choose Require Face ID, Touch ID or Passcode, and authenticate. The icon can remain visible while opening the app requires authentication.
Does this erase copies elsewhere?
Not every app can be locked. Device authentication is not an independent password for each app, and the lock applies only to this device.
Will this change another device?
Check each device separately. App lock and hide status is device-specific; iCloud Photos can synchronize photo hidden status.
Is this an independent password?
Device authentication is different from an independent app or vault password. Inspect the fallback offered.
How should I verify it?
Practice with an ordinary sample, close the app and reopen it. Confirm both visibility and authentication before relying on the result.
Can I reverse this?
Use the documented unhide or unlock action. Reversing visibility does not recover deleted content or revoke earlier sharing.