LG Optimus quest LTE User Manual page 109

Settings
108
Encrypt phone
Opens a screen that encrypts data on the phone for security. You will be
required to enter a PIN or password to decrypt your phone each time you
power it on.
Encrypt SD Card
Opens a screen that encrypts data on the SD card for security. You will be
required to enter a PIN or password to decrypt the data each time you
power it on.
Password typing visible
Checkmark to briefly show each character of passwords as you enter them
so that you can see what you enter.
Phone administrators
Add or remove phone administrators.
Unknown sources
Allow installation of non-Play Store applications.
Trusted credentials
Checkmark to allow applications to access your phone's encrypted store of
secure certificates and related passwords and other credentials. You use
credential storage to establish some kinds of VPN and Wi-Fi connections. If
you have not set a password for the secure credential storage, this setting
is dimmed.