Presuming Windows 10, Settings, Privacy, Microphone Pane is where you can toggle global access to the microphone on/off and then if turned on, then further control which apps can or cannot access the microphone.
As to checking Microphone record levels, I find it easiest to go to Settings, Time & Language, Speech pane then activating the Get Started button under the Microphone, set up for speech recognition section.
Brian - Windows 10 Pro, 64-Bit, Version 1909, Build 18363
Tolerance is the positive and cordial effort to understand another's beliefs, practices, and habits without necessarily sharing or accepting them.
~ Joshua Liebman