For the Unity and simultaneous test on the android there is such a thing as Unity Remote 4 .
Unity Remote 4 is a program that helps to implement remote control to the project in the Unity Editor.
Usually this application is downloaded on the android (via google play for example), and you must also check the Android Debugging option in the Debugging settings (enable the Android Debug bridge "adb" intefrace) .
We must not forget to connect the phone to the computer (or what is the development).
When you start the application, you will see the following image:

In Unity, you need to switch to the Android platform. And also in the settings
Edit → Project Settings → Editor in the Unity Remote → Device item, select Any Android Device

After that, if you click Play - the game should start in the editor and on the phone too
If there is no phone, then this chip can only roll with the android emulator installed via AVD Manager.exe. Moreover, the CPU / ABI setting must be ARM armeabi . If the value is Intel x86 will not work.
Sample settings for AVD:

After installing the emulator, you need to install Unity Remote 4 from apk into the emulator using the command: adb.exe install adb.exe install path/to/apk (Windows) or adb install path/to/apk (Linux / Mac).
Everything else is the same as when working with the phone - to make settings in Unity and so on. After all installations, it is desirable to restart Unity!