There are two levels of protection for marks, unregistered and registered. Once a brand uses a trademark, that business owns that mark (assuming no one is already using it). The business develops rights by using the mark consistently and defending it. However, ownership rights generally fall under common law protection and may only apply to the geographic area where the business sells and fulfills its goods or services. This method of trademarking through consistent use works best for well-known, highly visible brands.
The second method of protecting your trademark or service mark is to register your mark. Marks can be registered at the state level, which protects your mark as long as you are only doing business within state lines. For national protection and the ability to defend your mark in Federal Court, you must register your mark with the United States Patent Office.