Any Indian citizen with a current account in the name of his/her business can start a sole proprietorship. Registration may or may not be required, depending on the type of business that is planned to be established. However, to open a current account, banks typically require a Shops & Establishments Registration.

A Sole Proprietorship business does not take more than 15 days to set up and start functioning. This simplicity makes it popular among small traders and merchants. It's also much cheaper, of course. This is the other reason why it's the most widely used business structure.

Most local businesses are run as sole proprietorships, from grocery stores to fast-food vendors, and even small traders and manufacturers. That is not to say that larger businesses cannot operate as sole proprietorships, they can! Jewellery shops are sole proprietors, but it is not recommended.

This depends on the business you're in. It is compulsory for any business whose turnover in a financial year exceeds ₹20 lakhs (₹10 lakhs in the case of North Eastern states) to get a GST registration. For businesses that are involved in selling goods or services to customers out of a commercial establishment, it is mandatory to register under Shops and Establishments Act.

Yes, it is much cheaper to run an LLP than a private limited company. Mostly because compliances, such as an audit, apply to LLPs only after their turnover is sizable. Most LLPs spend about half as much as private limited companies, in their first year on registrations and compliance work.

The procedure involved is a little tedious, but it is possible. It is very common for sole proprietors to convert into partnerships or private limited companies at a later stage of their businesses.