i made flappy game i want to stop my bird and after press any place start jumping because when i start the game its fall down
You could put a small invisible platform under your Bird. This will stop it falling. Then will be left behind once the user starts tapping.
You can tweak gravity and change the World UI button from "Touch to Fly/Jump" and add up & down button, or a simple sort of "Joystick" button slide up go up, slide down go down, etc etc