If you're starting a sole proprietorship or a partnership, you have the option of choosing a business name or dba (doing business as) for your business. This is known as a fictitious business name. If you want to operate your business under a name other than your own (for instance, Carol Axelrod dba Darling Donut Shoppe), you may be required by the county, city or state to register your fictitious name.
In some states, you have to place a fictitious name ad in your local newspaper for a certain amount of time. In most cases, the newspaper that prints this fictitious name ad will also file the necessary papers with the county for a small fee.