Rajesh, 

Mode of admission to evry Indian Institute of information technology and IIIT BHUBANESHWAR IS

One needs to take the JEE (Main) exam and either secure at least 75% marks (65% for SC/ST/PwD) in Class XII or be within the category-wise top 20 percentile in his/her respective Class XII board examination.

Admissions are done on the basis of rank in JEE (Main) through JoSAA Counselling and CSAB Special Round.

And for IIIT HYDERABAD AND BANGALORE you need to have a good jee mains score and separately apply for their counselling at their respective websites.

Hope it helps