This will be the default entity if you operate a business by yourself. No formalities or filings are necessary to receive this status, but there are significant drawbacks that may make sole proprietorship the least attractive choice. One drawback is that you might need to file an assumed business name. Unless your company name includes the full legal name of the business owner, the business name must be registered as an assumed business name with your state's business registry. For a number reasons, associating your full name to your business may not be attractive.
Privacy is an issue.
And you may not want to give the appearance to the public that your business is a one-person show. The good news is that a sole proprietorship will have neutral or pass-through tax consequences. The bad news is that all your personal assets are at stake in the event that your company is sued or your company breaches a contract. Further, a sole proprietorship is not well positioned to receive any sort of formal outside investment. In the absence of any formal filing, if two or more persons do business together, they are deemed to have formed a general partnership.