Hey Sheenam.

Admission in 5 year integrated courses like BBA LLB is done through various different entrance examinations and on the basis of your score/ rank in it. The eligibility criteria for most of the entrances ranges between a minimum aggregate of atleast 45-55% markn in your 12th boards from any stream. Here is a list of various entrances for BBA LLB-

CLAT- All National Law Universities

SLAT- Symbiosis Law School

LSAT- All Private Law colleges

IPU CET- IP University

 MHCET-  law colleges in Maharashtra 

 TS LAWCET Etc

Best of luck.