I'm an aerospace engineering student of 3rd year. I want to become an astronaut could you explain in detail where to study, which exam?

Hello Rohith, aah, it's very nice to hear from you that you want to become an astronaut. Unfortunately no country accepts nationals from any other country to become astronauts. In India, only pilots of IAF have been allowed to become astronauts. You have to take your pick. Best wishes to you.