I have done 12th in arts now i want to do bachelor in library. how can i do?

Hello. you can do LLB but you have to decide from which college you have to do. if you wish to do from NLU's or other best institutes then apply for CLAT(common law admission test).

Dear Fd14020, it is very simple go and join any university which runs B Lib degree anyd enjoy as librarian.If you wish you can do M Lib and Ph.D also in same field.good luck