Why does my WiFi not show up in the list on MacBook?

Is your wifi not showing only in the macbook ?

IS it accessible for other devices?

if it is problem only with one device ,reset the network settings and restart the system.

still your facing the issue check for available software updates.

I would assume that if it does not show up on the list it is because it is not detected. You ned to verify that it i actually working. As your internet provider for assistance to resolve the problem.