How to become cosmologist.......
Hello Suraj,
Cosmologists are people that have an inherent interest in knowing about the universe's origin and studying the celestial bodies.
The basic requirement is to get a Bachelor's degree in Physics, astronomy, astrophysics, mathematics or engineering with a relevant subject like aerospace engineering.
This degree can get you like a Research Assistant job in cosmology.
You can pursue Master's or doctoral degree in Physics, Astrophysics, Astronomy, Aerospace engineering or Mathematics so that you can do research yourself or become a cosmology professor in a university.
Hope this helps.