How to enable App sources other than Google Play in NOVO Vi?

Settings that allow you to download apps from other sources than Google Play in NOVO Vi

We all know that Google Play is the default app in any Android device. It has most of the apps you need. But what if you suddenly need something else which you cannot find in the Google Play.

First of all, go to Settings and under System you will find "Security". Click on it.
Then choose "Unknown sources" and tick it.
You should get the information that installing an application from unknown sources could be very harmful to your device.
If you are 100% certain you want to do that click OK and it should get ticked.