Works for Secret Inbox whether or not it has its own passcode. No download needed.
Touch and hold Secret Inbox's icon, tap Require Face ID, then confirm. On iOS 18 and later that puts Secret Inbox behind Face ID, Touch ID or your passcode; choose Hide and Require Face ID instead to move it into App Library's Hidden folder as well.
Lock Secret Inbox with Face ID
- Find Secret Inbox on your Home Screen or in App Library.
- Touch and hold the icon until the quick-actions menu opens.
- Tap Require Face ID (or Require Touch ID / Require Passcode, depending on your iPhone).
- Tap Require Face ID again to confirm. Secret Inbox now asks for authentication every time it opens.
To test it, close Secret Inbox from the App Switcher and open it again. You should see the Face ID prompt before any content appears.
Hide Secret Inbox in App Library
- Touch and hold Secret Inbox's icon and tap Require Face ID.
- Choose Hide and Require Face ID instead of Require Face ID.
- Confirm. The icon leaves your Home Screen and moves to the Hidden folder at the bottom of App Library.
- To open it later, swipe to App Library, tap Hidden and authenticate.
Hiding also locks the app. To undo either, touch and hold the icon again and choose Don't Require Face ID.
Why lock Secret Inbox?
Secret Inbox is a secure email app, the kind of app that tends to hold personal information you would not want on screen if someone borrows your unlocked phone. Email apps see every message and contact. Third-party mail clients may route mail through their own servers to offer features like push or AI summaries.
Utilities range from calculators to VPNs, so their labels vary more than any other category. A simple tool that collects identifiers and usage data for tracking is a sign of advertising SDKs.
A lock answers one question — who can open the app on this iPhone. It does not change what Secret Inbox sends to its developer; for that, see Secret Inbox's full privacy report.
What the lock does and does not do
It does
- Ask for Face ID, Touch ID or passcode every time Secret Inbox opens
- Hide message previews in notifications
- Keep Secret Inbox's content out of Spotlight and Siri suggestions
- With Hide, remove the icon from the Home Screen
It does not
- Stop someone who knows your passcode
- Encrypt or change how Secret Inbox stores data
- Sync to your iPad or other devices
- Remove Secret Inbox from purchase history or Screen Time reports
Don't see Require Face ID?
- Update to iOS 18 or later in Settings › General › Software Update.
- Make sure a passcode is set in Settings › Face ID & Passcode; the lock needs one.
- Some Apple apps (Settings, Calculator, Camera, Maps, Find My, Clock) cannot be locked or hidden.
- If your iPhone is managed by work or school, the option may be restricted.
Other settings worth checking for Secret Inbox
Notifications
Settings › Notifications › Secret Inbox › Show Previews: When Unlocked keeps message and account details off the Lock Screen.
Secret Inbox's full privacy label
The developer states that no data is collected from this app.
Lock these apps too
After you lock Secret Inbox
Done. You have applied every control the label points to.
FAQ
Does Secret Inbox have its own passcode?
What happens to Secret Inbox's notifications when it is locked?
Can someone who knows my passcode open a locked app?
Is a locked Secret Inbox encrypted?
Why can't I see the Require Face ID option?
Does hiding Secret Inbox remove it from my purchase history?
Is Secret Inbox safe? Full privacy report →Does Secret Inbox track you? →Lock an app: A–Z →All utilities apps →