Hey.
LL.B.is the full form of Legum Baccalaureus which means Bachelor of Law. BL is also used for Bachelor of Law. There are 2 types of Law courses in India-  3 year LLB which can be pursued after you have completed any graduation degree like BA, BCOM etc separately and a 5 year integrated law course which combines an Undergraduate degree with Law. Admission in top colleges for Law is done through Entrance examinations.
If you are interested in 5 year Integrated course of Law after 12th then the forms to be filled are-

CLAT- All National Law Universities

AILET- National Law University Delhi

SLAT- Symbiosis Law School

LSAT- All Private Law colleges

IPU CET- IP University

PU BA/BCOM LLb- Panjab University, Chandigarh

MHCET- GLC Mumbai, ILS Pune, and other law colleges in Maharashtra

Christ University

TS LAWCET

Etc

For 3 year LLB-
Here is a list of law entrances for 3 year LLB course

- DU LLB - Delhi University

MH CET- GLC mumbai, ILS Pune and other colleges in Maharashtra

SLAT- Symbiosis Law school

PU LLB- Panjab University, Chandigarh 

LSAT- Jindal global Law school, IIT Kharagpur and other private law colleges

BHU LLB- Banaras Hindu University

BVP LLB- Bharatiya Vidyapeeth

TS LAWCET Etc

Best of luck!