I have completed bsc physics honours. I want to do a job oriented course in masters. which is best for me (MSC -it) or post diploma

It seems you are not really interested in pursuit of Physics in Future after B.Sc., and rather want to pursue a Degree guaranteeing strong career prospects. In that case you do have many options, which, I'm going to lost below

1. MCA : Try pursuing MCA from some of the Good NITs, through NIMCET Exam or some of the Good Private Universities like Manipal or VIT, having good career scope and placement Prospects.

https://www.careers360.com/courses/mca-master-of-computer-applications/amp

2. MBA : You may prepare for Examinations like CAT, XAT, MAT, IIFT and secure your place in one of the NIR Top 50 B Schools, having great faculty, infrastructure, facilities and providing huge scope and impetus to training and placements.

https://www.careers360.com/courses/mba-master-of-business-administration

3. PG/Diploma (Data Science) : Many Online Education Platforms like Upgrad and Simplilearn have started Certification Programs and PG Diploma in domains like Data Science, Analytics and AI. This is aa very new rising trend and can be done from Home, and yeah, the Platforms do even help you with Placement Assistance after completing the Diploma.

4. Government/State Exams : You may prepare for any of them UPSC/SSC CGL/RRB/SBI PO/RBI Grade B/State Civil Services/PCS

5. Incase you wish to compete with Engineering Aspirants, you may complete your AMIE Degree in your Domain of Interest first in a year besides parallely preparing for GATE. After GATE, you may join one of the Good IITs and pursue a M.Tech in Engineering.