Does height really increase after 20 yrs of age by yoga and other exercises , if yes then how much, does anybody has exact proof or any idea who's increases his/her height after their teen age by exercisin

There is no exercise that can increase your height - that is genetically set in stone.

You can't increase your height. But you can fake it. Good posture can add inches, so can well cut clothes, high heels and the most important thing is attitude. I have a friend and people who guess her height always say around 5 foot 6. She's actually 4 foot 11, but seems so much taller because she's so dynamic and assertive.