How can I set my microphone?

So I forgot where is the microphone settings. 

Can somebody please point to me where I can find the the microphone setting to pick the right microphone? 

Also...  Could it be I am recording from 2 different microphones at once?   In the audio picture file it looks like 2 identical audio recordings.   Some of the recording I have done it sounds like I have an echo.

How can I fix the echo???

Thank you 🙂