Below is the list of parameters on Installer policy settings tab:
Application installer lock
If set, there will be no possibility to install applications on the device.
Availability: Android, Apple, Windows Phone 8.1/10, Device Owner devices
Notification when application installation is blocked
You can set a notification that will appear on a device when user tries to install application. Default: Application installation is not allowed
Manual installation of the root certificate lock
If set, there will be no possibility to install the root certificate manually.
Availability: Windows Phone 8.1/10