Hello Mamta,

After class 12th, you need to give entrance exam like NEET to get admission in undergraduate medical course like MBBS. After that, in post graduate, you can choose specialisations in MD. If by great scope you mean most money, orthopaedic doctors generally are among the highest paid, and cardiologists/surgeons/gynaecologists also earn very much.

Moreover, you can get a medical degree from a foreign university, that will provide you more money if you practice over there, as conversion ratio to Indian currency is high.

I am providing you the name of few courses below as there are many available for science students after 12th and these are having good scope as well -
MBBS
BAMS (Ayurvedic)
BHMS (Homoeopathy)
BUMS (Unani)
BDS
Bachelor of Veterinary Science & Animal Husbandry (B.VSc AH)
Bachelor of Naturopathy & Yogic Science (BNYS)
Bachelor of Physiotherapy
B.Sc. Nursing
General Nursing
BMLT (Medical Lab Technology)
Paramedical Courses
B.Sc. Degree
Bachelor of Pharmacy

Note :- Please consider your interest and potential also before making any decision.

Hope this helps!!!

Good Luck!!!!