I have a 1998 Mercedes ML320 the key gets stuck in the ingnition sometimes it comes out when I move the steering wheel sometimes I have start the car and turn it off any idea

This happened mto me and it turned out my shifter mechanism was damaged, the shift interlock was not working. If you are going to try to fix that yourself, just becareful that the air bag doesn't deploy... ouch...
Sometimes they have a manuel release button, see if there is a small square cover close to the ignition switch either above it or below it. If there is one take something and pry off the cover, I used a metal finger nail file. Then take a small enough object to insert into the hole under the cover( I used a bobby pin) and you should be able to pull out the key. If that's not an option, you could remove the ignition fuse to disable the vehicle for the night.