The most sought after institutes have their own independent admission processes.
However, all of them have a 2-stage process:

Stage 1: Written admission test.
Multiple-choice tests in maths, verbal, reading, logic & business awareness conducted in centres across India.
Read more about specific admission tests

Stage 2: Personality Assessment
Those who qualify through Stage 1 normally proceed to two stages of personality assessment:

Group Discussion: Your performance in a group, while discussing a topic of current importance, is evaluated by a panel of judges. Read more about GDs

Personal Interview: You are interviewed by a panel of specialists. Read more about the interview process .