My clutch has little resistance and when I go to shift gears it will not shift. on 2000 Hyundai Elantra

it wont shift properly and it will not shift the gears right.

2 answers
Does it shift into gear with the engine off? if not, you have a problem with your transmission...if it does, you have a problem with your hydraulics...and I would recommend you replace both the master and slave cylinders.
sounds like you need a new clutch or slave cylinder