HI, BBA and BBM both are UG courses.
BBA makes the aspirants efficient with required skills in administration. A BBA degree holder, after successful completion of studies, can search for a prosperous job or can go for higher study options. Higher study options such as MBA can offer enormous job openings to deserving candidates.

BBM is also a 3 year UG course in management. Those who have completed class XII can apply to get an admission in BBM. After the bachelor degree, the students can grab a better job in private or government sector. They also have higher study options such as MBA. Other than MBA, the students can also go for MS in finance or Accounting.
There is not much difference, it just matters what  you want to do next.
Good Luck.