In order to pursue MBA one needs to complete his graduation and then appear for CAT/CET and clear it. Depending on the score you are allotted a college.
The course usually is for 2 years,but it also depends on the course that you select. There are others which are for 3 years-part time, 1 year and PG diplomas. It depends on your choice of the program.
Certain diploma course do not require you to give the entrances.
MBAs offer various specializations like HR, marketing, finance, resource, operations etc.
Let us know what you interests you and we will be able to give you specific details.
Hope this helps.