There are three primary ways to operate your business: as a limited liability company (LLC), a corporation that qualifies for certain tax treatment (S Corp), or as an unincorporated enterprise ("doing business as" or DBA).
An LLC and an S Corp achieve the same two primary goals: protecting your personal assets from business debts and liabilities, and avoiding double taxation. Both are considered "pass through" entities, meaning the income is not taxed twice at the corporate level and in your personal income taxes.
An LLC by definition is a pass through entity. An S Corp must meet certain requirements under the IRS code in order to qualify for pass through treatment. Most of our clients begin as an LLC, and consider changing to an S Corp when the amount of revenue makes that more economically beneficial.
A DBA is not an entity at all- it is just you doing business as whatever name you have picked for your business. Though you avoid double taxation that way, you have no protection for your personal assets if your business has debts or liabilities.