Problem with apk screen

I made a project on unity to android and that is the menu scene:

But when i open the builded apk on my phone the scene transform to this:

I don’t know why this happen. If anyone can help me I will be very happy.

The aspect ratio changed, and if you haven’t set up your UI correctly using anchor points, then this is going to happen (also you have to deal with the view being wider than your ground width). It’s always good to change the aspect ratio to many things in the editor to test what could happen to your game. You can do this in the game tab, click the aspect drop down and select different ones- 5:4, 16:10, 16:9, etc.