If your mobile device has sensitive information on it, then you may want to consider encryption. Encryption converts the data on your phone into an unreadable form. This means that, when you turn your device on, you’ll need a passcode or pin to decrypt the device and the data on it.
For Android users:
Step 1: Click Settings
Step 2: Tap the More tab
Step 3: Tap Security
Step 4: Tap Encrypt device
You should set the screen lock if you have not already. Be aware that whatever screen lock you choose will be used for starting the device and getting past your lock screen. Should you select to use a strong password, you’ll be typing that password every single time you wake up your phone. This can be a bit cumbersome — but if you’re looking for very strong security on your device, this is the way to go.
For iPhone users:
Step 1: Go to your iPhone’s settings.
Step 2: Scroll down and click on “Touch ID & Passcode” (for older devices without the fingerprint scanner, it is “passcode”).
Step 3: Tap on “Turn Passcode On” option.
Step 4: Set a strong passcode or password. You can set a strong four-digit, alphanumeric password or a longer numerical passcode.
Step 5: Ensure data protection is enabled. To verify this has been enabled, go back to the settings. When you scroll down to the bottom of the page, you will see “Data protection is enabled”.
You can find further information here.