How to disable a passcode lock?
To disable a passcode lock
1. Open the Bigin app on your iPhone.
2. Tap the More 
icon at the bottom right of the screen.
3. Select Settings 
.
Under "Manage Privacy", you can find the title "Privacy & Security".
4. Tap on Privacy & Security > Passcode Lock.
5. Enter the current passcode.
6. Select "Turn Passcode Off".
7. Enter your current passcode once more.
Note: Once you've disabled the passcode, the next time you tap on the Bigin app icon to open the app, you won't need to use a passcode to enter the app.