Allow App Installation from Unknown Sources - ASUS
Your device and personal data are more vulnerable to threats such as Ransomware from apps downloaded from unknown sources. Here's some additional info about downloading from unknown sources and protecting your device against Ransomware.
From a Home screen, navigate: Apps icon > Settings .
Tap Application manager.
Tap the desired app (e.g., Chrome, Gmail, Drive, etc.).
Tap Install unknown apps.
Tap the Unknown sources switch to turn on or off .