Prevent Auto-download/ install of Apps/Ads on Micromax Phones android installing apps without my knowledge. It also showing annoying popups.
How to resolve this issue?

Android version : 5.1 Lollipop
Device: Micromax Canvas 6

Everytime i factory reset, it will fix the issue. After some days, it will start to show popups from Amazon, Myntra like shopping sites.
Phone is installing apps in the background.
As I know every Android OS phone have the option "Auto-update apps" in the Google Play Settings. For the first, I would completly disable that!

On the site of a Micromax Canvas blog, there is already an article about this issue. I found serval solutions below there  ⬇ ⬇ ⬇



If your Device is rooted then our friends of XDA-Developers already have it: 


  
  Disable the Software Update application
  
  
  Now that you have gained root access and ADB is up and running, you
  can continue with disabling the dreaded application responsible for
  the silent installs and unwanted ads. All you need to do now is to
  fire up a command prompt, make sure the prompt is at the directory of
  your ADB binary, and execute the following command:
  
  adb shell pm disable com.adups.fota




For non-rooted device you can try to disable the Software Update package:


Go to Settings
Apps
All Apps
Then disable or uninstall there all apps/ packages that are responsible for updates and install. I don't know which and what they're called. I tried to find out but I looks like it is always an other. Whether it's FWUpgrade.apk or Software Update or the app itself.


Try also to uncheck: Settings–&gt;About Phone–&gt; System/Software update

For more just google itself, I found many other possibilities but I can't list all them.