Works for BluLines whether or not it has its own passcode. No download needed.
Touch and hold BluLines' icon, tap Require Face ID, then confirm. On iOS 18 and later that puts BluLines 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 BluLines with Face ID
- Find BluLines 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. BluLines now asks for authentication every time it opens.
To test it, close BluLines from the App Switcher and open it again. You should see the Face ID prompt before any content appears.
Hide BluLines in App Library
- Touch and hold BluLines' 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 BluLines?
BluLines' privacy label lists location — the kind of data you would not want on screen if someone borrows your unlocked phone. Notes apps quietly collect some of your most personal writing. 'Encrypted' can mean encrypted in transit, at rest on the server, or end-to-end — only the last keeps the developer out.
Productivity apps tend to collect the work you do in them — documents, notes and files — so User Content is common. The question is whether it syncs to the developer's servers and how it is protected there.
A lock answers one question — who can open the app on this iPhone. It does not change what BluLines sends to its developer; for that, see BluLines' full privacy report.
What the lock does and does not do
It does
- Ask for Face ID, Touch ID or passcode every time BluLines opens
- Hide message previews in notifications
- Keep BluLines' 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 BluLines stores data
- Sync to your iPad or other devices
- Remove BluLines 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 BluLines
Tracking
Settings › Privacy & Security › Tracking. If “Allow Apps to Request to Track” is off, apps cannot ask, and they are told to treat you as having declined. You can also turn it off for this app alone.
Location
Settings › Privacy & Security › Location Services › BluLines. Choose While Using or Never, and switch off Precise Location if a city-level answer is enough.
Notifications
Settings › Notifications › BluLines › Show Previews: When Unlocked keeps message and account details off the Lock Screen.
BluLines' full privacy label
None declared
Lock these apps too
After you lock BluLines
Done. You have applied every control the label points to.
FAQ
Does BluLines have its own passcode?
What happens to BluLines' notifications when it is locked?
Can someone who knows my passcode open a locked app?
Is a locked BluLines encrypted?
Why can't I see the Require Face ID option?
Does hiding BluLines remove it from my purchase history?
Is BluLines safe? Full privacy report →Does BluLines track you? →Lock an app: A–Z →All productivity apps →