I released the pin that holds the gear shift cable and removed cable from arm, than very careful tap the arm on transmission towards radiator, this will put it into park so engine will start, then check cable-it may need to be replaced to work properly.
Check and see if you have brake lights - If there are no brake lights then your shifter release solenoid will not release the shifter, it will be stuck in park. If this has happened then please check the wiring on the brake light switch which is located on the brake pedal. You will probably find a broken wire.
It sounds like the transmission shifter linkage is disconnected.
If you cannot move the shifter out of the park position then you have a problem with the shifter cable or the brake safety lock. If you can move the shifter to the drive position, and it doesnt go in gear then you are a few quarts low on transmission fluid
If diff lock light is stuck on DO NOT DRIVE IT ON THE ROAD it will break. Ensure shifter is in diff lock off position and slowly drive forward and back in a straight line.
Does it have an automatic transmission? If yes look on the lower part of the colunm as you move the shifter you will notice it moving , When you move the shifter from drive towards park note the direction it moves then reach done there and with your hand continue to rotate the collar as you place the shifter in park this will release the locking mechanism so the key will come out.
remove the plastic ring around the button you push on the shifter to switch gears, the car thinks it's still in drive and won't release the key. The ring removal will release it, but the actual fix involves replacing the whole shifter...
Year, make,model, engine size & symptoms are always a help. Without that guesses are the best you can get. It may be the shifter interlock. There may be a shifter release button in the shifter area or some information in your owners manual. Possibly the brake pedal shift release that lets the shifter only move if the pedal has been depressed. If that's not a solution you're going to have to get into the release and see what the problem is.
Check the brake switch on the brake pedal, if the switch is bad or a fuse is blown, the shifter will not release.
Perhaps your brake interlock isn't working. That's the deveice that releases the shifter when you depress the brake. Most cars have a manual override. You probably will remove a cover and press a button with a pen or screwdriver. It should be near the shifter. Check your owner's manual for details.
The brake pedal shifter release switch is disengaged. You will need to go under the driver kick panel area and manually press the switch (look to see if the switch wire harness is loose)
automatic or manual?
If your dirt bike is stuck in gear, the shifter fork is most likely bent or broken. Changing the shifter fork requires splitting the case.