Hey Lata.

You can join Indian Air Force after the graduation in the following ways.

You can be a part of any of the three branches of the Airforce which are:

Flying Branch

Technical Branch

Ground Duties Branch

Joining Indian Air Force After Graduation – AFCAT Entries

Air Force Common Admission Test or AFCAT is by far the biggest exam conducted for entry into the IAF. This test allows entries for a good number of vacancies in all the three branches of the Airforce which are Flying, Technical and Ground Duties.

Though there are other ways also to join Indian Air Force after graduation, those methods are limited to male candidates. Ypu can appear for thia exam. 

Hope this helps. All the best.