Hello Edapha

Yes and No.

There are some limited seats in each department of IIT which are offered to students by their gate score(First Rank First served). If you got such a M.Tech seat, congrats your hardwork has been paid off.

Later as the score of the students for those who applied in each departments are below the threshold score, then the vaccant seats are filled by conducting interviews. Don't worry for interviews, as the interviewers are looking for your potential(and not skills). If you clear such grounds, congrats.