...
You definitely should have a passcode set up, though, and not just the default 4-digit one. Use a stronger, longer passcode or passphrase in your Passcode settings your Passcode settings (at least 6 digits long). Even just two digits more make your iPhone much more secure.
...
On Android devices, the lock screen and the device encryption are separate but related. You can't encrypt your Android device without the screen lock turned on, and the encryption password is tied to the screen lock passcode.
- Unless you have a full battery charge, plug in your device before beginning.
- Set a password of at least six characters that contains at least one number if you haven't already done this. Because this is also your screen unlock code, choose one that's easy to enter.
- Click Settings > Security > Encrypt Device. On some phones, you may need to choose Storage > Storage encryption or Storage > Lock screen and security > Other security settings to find the encrypt option.
- Follow the onscreen instructions to complete the process.
...