Dear Aspirant
First is please clear which registeration you are asking, for the exam or for counseling
If it is related to exam you have to register NEET and no need of filling different form, for different medical subject
If you care asking about counseling so you have to check with college and university website they will announce the counseling schedule accordingly. And they also describe same form for BAMS and MBBS or it should be different.
All the best
I hope this information is helpful for you
Thank you
Team Career 360