File -> Build Settings
Build Settings
Follow the steps below to confirm the Api Compatibility Level is set correctly in your Unity Project.
In Unity, navigate to File -> Build Settings. Select Player Settings.
Under Player tab, select Other Settings. Scroll down to Configuration.
Ensure .NET Framework and IL2CPP are selected
Android specific build settings
After you’re done, go back to the Build Settings window, ensure the scene is selected. Unity will then build the necessary files to the folder location of your choosing (create a new UI Build folder for these files).
Building to android is straight forward, it creates a .apk file which can be transferred to your android device via usb or bluetooth.