Security, How to encrypt Android devices
This page provides instructions on how to encrypt an Android device.
Instructions provided by Androidauthority.com: http://www.androidauthority.com/how-to-encrypt-android-device-326700/
Android 5.0 or higher
For Android handsets and tablets running Android 5.0 Lollipop or newer, you can navigate straight to the “Security” menu under settings. Getting here might be slightly different depending on your OEM, but with stock Android this can be found under Settings > Personal > Security.
Here you should see an option to “Encrypt phone” or “Encrypt tablet”. You’ll be asked to plug your phone in to charge while the process takes place, just to make sure that your phone doesn’t shut off and cause errors. If you haven’t done so already, you will be prompted to set lock screen PIN or password, which you will need to enter when you turn your phone on or unlock it in order to access your newly encrypted files. Be sure to remember this password!
Android 4.4 or lower
If you’re running a handset with Android 4.4 KitKat or lower, you will have to setup a PIN or password before starting up the encryption process. Fortunately this is simple enough, head on over to Settings > Security > Screen Lock. Here you can either pick a pattern, numbered PIN, or mixed password for your lock screen. This will be the same password used after encryption, so make a note of it.
Once that’s done, you can go back to the Security menu and hit “Encrypt phone” or “Encrypt tablet.” You’ll need to have your phone plugged in and read through the warning messages, and you will almost certainly have to confirm your PIN or password one last time before the encryption process starts.