microphone on intel macbook air not working

I know this is the IT support classic but, try rebooting as it sometime fixes the odd mic not working and camera not working issues.

Also check in system report to see if your mac is seeing the mic. Apple logo - About This Mac - System Report -Audio and it should be listed. Check your privacy setting to see if it's being blocked there.

Also try running only one app that has access to the mic, as from my experience running more than one application that used the mic courses confusion, as only one program should have access to the mic at any one time.

Have a look in Security and Privacy to see what applications are being allowed to use your MacBook Airs mic.

Also check the settings in Zoom and Skype to check your internal mic is selected as the mic.