There is nothing more scary then the thought of some stranger having access to your personal data. The first thing you can do is strengthen your log on password for you iPhone.
- Launch Settings.
- Tap Passcode (or Touch ID & Passcode).
- Enter your existing 4-digit or 6-digit passcode, if you have one.
- Tap Change Passcode
- Re-enter your existing passcode if you have one.
- Tap Passcode Options.
- Tap Custom Alphanumeric Code.
- Enter your new long, strong alphanumeric password.
- Re-enter your new long, strong alphanumeric password.