I need to talk to someone about being able to use a microphone to have audio input on audacity. I have a tascam us-122 audio interface with a microphone and i think it works, but it doesn’t translate to me being able to record on audacity. when i pull up “preferences” on the edit menu, the tascam us-122 isn’t an option. What can I do? 
The first step is to go to the sound control panel on your computer and see if you can see and select the us-122 there. Do this while Audacity is not running. Quite often the sound hardware in the computer won’t let Audacity change the input selection.
I assume that in Audacity you’re going to Preferences > Devices?
What computer, OS and version of Audacity are you using?
– Bill