Hey bharti,
Admission to the course is generally entrance exam based.The entrance tests areorganized at national, state or university level by various authorities. A merit list isprepared on the basis of qualifying examination or entrance examination.

Most of the colleges conduct separate entrance exam for admission to BBA course. Some of the entrance exams conducted forBBA course are as follows:

AIMA UGATAIMA Under Graduate Aptitude Test (UGAT) is a national level examination conducted annually by All India Management Association (AIMA). Itis conducted to screen capable candidates for admission in various courses such as BBA, BCA, Integrated MBA, BHM, B. Com etc.SETSET or Symbiosis Entrance Test is acommon test conducted by Symbiosis International University for admission in undergraduate courses in the fields of Law, General, Design, Engineering and Health Science.IPU CETIPU CET 2017 (IP University Common Entrance Test) is a university level entrance exam conducted for admission to 60 undergraduate, postgraduateand research courses.

Admission to BBA course is also done on the basis of Lateral entry i.e. entrance to the course in second year. Universities like Lovely Professional University and Annamalai University provide this option.The eligibility for this is qualification offirst year examination from a recognised university with a minimum aggregate score of 50%.
I hope you will find your best one :)
Cheers !!