I use the Android zoom application to share the screen with other people. You all see my screen sharing fine, but the application's audio is muted. I can mute and unmute the hardware microphone (it picks up ambient noise or my language) but the sound of the Android application itself (e.g. video playback, system sounds, YouTube video, etc.) is not present.
In the desktop version of Zoom, when you share your screen, there is a check box for sharing system sounds or the screen you are sharing. However, such an option is not displayed in the Android version.
I'm using Samsung ActiveTab 2 (on Samsung's Android 9, I think).