Hi there. 

A total of 3 medical related competitive examinations occur in India for undergraduation candidates. 

These are NEET, AIIMS, JIPMER. 

NEET examinations are for students who are between the age range of 17 years - 25 years (for general candidates) with 50% aggregate marks in Class XII boards with Physics, Chemistry and Biology. Cracking NEET one can get admissions into colleges (all government and private colleges) for courses like MBBS, BDS, BAMS, BHMS. Please refer to the following link for more information: 

https://medicine.careers360.com/exams/neet

AIIMS entrance exam is conducted for securing admissions in MBBS courses in All India Institute of Medical Sciences (there are a total of 9 AIIMS in the country). AIIMS Delhi is the rank 1 college of India for the course of MBBS. For more relevant information check the following link: 

https://www.google.co.in/amp/s/medicine.careers360.com/articles/aiims-mbbs-2019/amp

JIPMER examinations is conducted for admission in MBBS and BDS courses in Jawaharlal Institute of Postgraduate Medical Education and Research. There are two campuses of JIPMER, one is Pudducherry other in Karaikal. Kindly refer to the following link for more information: 

https://www.google.co.in/amp/s/medicine.careers360.com/articles/jipmer-2019/amp

Hope this helps.