Hello student if you're willing to pursue M.tech from Osmania University then you must have to appear and qualify GATE as admission is on the basis of marks obtained in GATE Examination only.

However in JNTU Hyderabad admission is through GATE or PGECET

ELIGIBILITY - Candidates must have passed BE Or B.tech with minimum 55 percent marks from a recognized university.

Feel free to comment if you've any doubt

Good luck