I want to do business. Is it necessary to do MBA for it or can I join other course that can help me in my business?

It is not necessary, but it provides a good platform to generate and materialise ideas, and build contacts. Kindly go through the websites of the institutes offering business management courses.

Yes MBA will give you a good basic knowledge of business scenarios and business terms. It will be like theory and then practical. If you directly go in business then you will get more learning through practical scenarios.