How to Change the Audio Device in Windows

Windows 10

1. Click the Start button.
2. Click the Settings (gear) icon.
3. Click System.
4. Click Sound.
   • Under Output, you can choose a new audio device to play audio from.
   • Under Input, you can choose a new audio device to record audio from.

Documentation

For Skype for Business, see Microsoft's official article:
Set Audio Device options - Microsoft Support