Hey Prateek !
Two of the most common exams that willing medical students study, in order to PG abroad are USMLE and PLAB.
You can do your MBBS from India and at the same time prepare for both these exams.
USMLE is for doing Residency under the US whereas PLAB is for the same in UK.
The pattern and form of both the exams are quite different. USMLE is generally a 3-Stage Exam whereas PLAB is a 2-Stage Exam.
Compared to PLAB, USMLE is tougher on its aspects.
But, it should be know that clearing these exams gives you a great deal of respect and opportunity to study under world class hospitals and universities. Most of the AIIMS-D and students prepare for these prestigious exams amd ace them too.

Hope this helps.

Good Luck !