The 2002 Nissan Altima has a hydraulic clutch and it can not be adjusted. The only thing you may be able to do is adjust the pedal travel. There may be a nut with a threaded rod on top of the pedal attachment point under your dashboard.
If the clutch feels funny, try bleeding it. If that is not working, try replacing the fluid. If you still have a problem you may need to replace the clutch.