A sole proprietorship is the simplest and most common structure chosen to start a business. It is an unincorporated business owned and run by one individual with no distinction between the business and you, the owner. You are entitled to all profits and are responsible for all your business’s debts, losses and liabilities.

You do not have to take any formal action to form a sole proprietorship. As long as you are the only owner, this status automatically comes from your business activities. In fact, you may already own one without knowing it. If you are a freelance writer, for example, you are a sole proprietor. But like all businesses, you need to obtain the necessary licenses and permits. Regulations vary by industry, state, and locality.

In Washington State, a sole proprietorship is indeed the simplest business structure and does not require formal registration with the state to be established. As a sole proprietor, you are personally responsible for all aspects of the business, including debts and liabilities. Profits from the business are also yours. However, you must comply with licensing requirements which can vary depending on the type of business, location, and industry. This may include obtaining a business license through the Washington State Department of Revenue's Business Licensing Service, as well as any other local or industry-specific permits. It's important to check with local city or county offices to ensure all necessary licenses and permits are acquired. Additionally, while not required, a sole proprietor may choose to register a trade name or 'Doing Business As' (DBA) with the state to operate under a name other than their legal name.