US does not have centralized rules about such things. It's in the hand of each university how they want to handle it.

Very few US universities will admit students with a 3 year bachelors from India. You can check that by writing a mail to the admissions office of the respective university.

Majority of the universities however will not accept the 3 year bachelors. For these universities, you will have to complete 16 years of formal education(10+2+4). This means that you will either have to complete a masters degree or some additional one year degree.

Note that most of the B-schools accept Indian 3 year bachelors nevertheless.