Sorry to say you, but you can not do LLB through correspondence after 12th; it can be done on regular basis only. to apply for the LLB regular course the applicant should have completed 12th with minimum 50% marks from any recognized board of India and you need to appear in the entrance examination.

For your reference here I am giving you the list of Top Law Colleges in India:

West Bengal National University of Juridical Sciences

National Law School of India University

Rajiv Gandhi National University Of Law

Hidayatullah National Law University

National Academy of Legal Studies and Research

Chanakya National Law University

Indian Law Society's Law College

Dr. Ram Manohar Lohiya National Law University

National Law Institute University

National Law University, Jodhpur

Faculty of Law, Jamia Millia Islamia

Gujarat National Law University

National University of Advanced Legal Studies

National Law University and Judicial Academy

National University of Study and Research

Faculty of Law, Aligarh Muslim University

National Law University, Odisha

National Law University, Delhi