Hello Swathi

Admission to MBBS course is done on the basis of marks obtained in the NEET UG entrance exam. To prepare for the exam, you should primarily refer NCERT textbooks. NCERT books are the best for clearing the basic concepts. You should also refer to the other important books for in depth knowledge.
Go through the link below to check the list of books -

https://medicine.careers360.com/articles/best-books-for-neet

Also, cutoff vary every year from college to college depending on various factors. Kindly mention the college name if you are seeking admission in any particular college.

Good Luck!