Shake the gear shifter then try. Turn the wheel HARD to the left, then try. Turn the wheel HARD to the right, then try. Depress the brake, then try. If none of that works, something in your steering column, or your ignition switch probably broke.
is the security light flashing? If so try turning the key on for ten minutes than try to crank the engine. Try this three times if no start turn the key on for thirty minutes than try cranking the engine. It should turn over if not You may need a new ignition switch. Or key. I need more info after you try this.