Sole proprietorship
A business owned and run by one person, with no separate legal identity from them.
Most small Indian businesses are proprietorships. There is nothing to incorporate: the business is you, it uses your PAN, and its income is your income. It is the quickest and cheapest way to start.
The catch is that you are personally liable for everything the business owes. As the business takes on staff, partners, investors or real risk, that is usually the reason to change its structure.
Learn it in a lesson
See also: LLP