Hi Prathyusha,

Hope you are doing well, Yes we can send more than one application for mtech in IIT Madras. It is for if you want to apply for more than 4 departments then you can submit separate applications to the department of your choice by paying the separate application fee. You can not edit the application and you need to reapply and pay the application fee. 

I hope it helps you!!!

Keep Smiling:)

Wish you good luck!:)