Microphone disable sounds on the Mac?

How do I turn off the microphone on the Mac? So it is recorded in a screen capture only the sounds coming from the laptop but not the ambient noise?

In the settings you can turn off the microphone under Privacy in the category Microphone for the various apps.

Or you put in the system settings under audio or how that means with microphone the volume simply to 0

But then no more sound is recorded.