You can do btech + mtech but not mtech directly you would have to get a btech degree first

Bachelor degree samosa khane ke liye hota hai kya?

Dear Reader,
M. Tech is a masters degree that means a post graduation degree.  M. Tech stands for masters of technology.  For doing a masters degree you need to complete your bachelors degree that is B. Tech or BE. Once you finish your B. Tech/ BE  you'll have to appear for GATE just like you might have appeared for JEE entrance exam for B. Tech.  GATE is an entrance exam for M. Tech as well as jobs in public sectors.
Good luck

Hello Mohit. No Mtech can't be done directly after 12th. For that firstly you need to have the bachelors degree and after that only you can go for Master degree in technology.