Hi M
I am Dave, an Independent Advisor, I will help you with this . . .
I need a bit more detail on your question, what type of Android device are you trying to install O365 on, and what size screen is on that device?
If that is an Android Phone or Tablet with a screen size less than 10/1" then you can install the free Office Android App on that device, there is no charge for that App on that size screen and no subscription is required to use the Office Apps
https://play.google.com/store/apps/details?id=c...
If your screen size is larger than 10.1", then you still install the Office App form the Google Play Store, and use the same Microsoft Account login that yu used to purchase Office 365