In this guide you will learn how to check which apps are using your microphone in Windows 10
1) Click on Start Menu Settings app.
2) Click on the Privacy section.
3) Select Microphone in the left sidebar.
4) In the right pane you will see the applications which have used your microphone. They will have “Last accessed” or “Currently in use” messsage below their name. Also you can turn them on or off.