It's impossible for us to answer such specific questions as to how to obtain a graduate degree in India or what the highest level of education is in your country. There are Master Degree courses available online, but many are scams, and even obtaining certification from a legitimate online program would deprive you of the face-to-face speaking and listening practice needed to master a second language.
Why do you want an advanced degree? Is it strictly to further your career, or is it because you want to become more proficient in English? If you strictly want to speak/read/write better English, you don't need an official Master's degree from a university; there are other courses you can take.
Student or Learner