Are you asking for JEE Main?

You can check the eligibiliy criteria below

-Students who are born on or after October 1, 1993 are eligible to apply for JEE Main 2018. For ST/SC/PwD relaxation for 5 years is provided.

- You must have passed 12thclass or qualifying exam in 2016 or 2017. Appearing students are also eligible for the exam
-It is mandatory for candidates to have taken 5 subjects in 12thor qualifying exam

The 5 subjects for B.Tech/ B.E. are:

1-Language, 2-Physics, 3-Mathematics, 4-Any one of (Chemistry, Biology, Biotechnology, Technical Vocational Subject), 5-Any other subject.

- To take admission in NITs/IITs/IIITs you must have 75% marks in your boards exam or you should be in top 20 percentile for SC/ST you must have 65% marks.

- You can attempt JEE Main 3 times.

Good Luck!!