Masters in Health Administration is a 2 year full time post graduation course and there is no entrance exam for it . The  autonomous college or private deemed universities might have entrance exams,

Yes after your B.Pharm you can join this course provided you must have secured minimum of 50% aggregate from a recognised Indian University.

The admissions will be  provided on the merit list using your B.Pharm marks.

For top institutes for this course go to the link below:

https://hospitality.careers360.com/articles/5198-Course-review_Master-s-in-Hospital-Administration