Its now 1 month i make a game on android, and i still cant find how to remove those ANDROID BUTTON MENU on screen 
how i can remove this bar on my phone with buttons (back, home , …) ?
I had this problem too and couldn’t find the answer anywhere. I mucked about and found a solution in the end.
I’m using 4.9.2, so I’m not sure if it’s recently been added, but the following works for me:
Open project, click Edit → Project Settings. On the left menu, find Android, under Platforms. Select that, then make sure the box is ticked that says Enable FullScreen Immersive on KitKat and above devices.
Finally, They Should Share This Kinda Stuff, Instead Of Their Useless Hair Simulation Works, Who Needs Simulated Hair? Seriously? WHO?! Theirs Like 100 Things Missing From The Engine, And 1000 Improvements Required