Why would you want to file an assumed name? What does it let you do?
DBA allows you as a sole proprietor to use a business name rather than your personal name. In some places you can use either your full name or part of your name plus a description of your product or service without filing an assumed name, e.g., Elena Garza Interior Design or J. Washington Investigataions. The exact rules vary from country to country and from state to state within the U.S., so check with your local business regulatory authority regarding your area. But if there's any implication that there are more people involved (Shawad & Sons, The Anderson Group, etc.), or if you just use the first name (Joe's Garage, Sam's Boat, etc.), you have to file an assumed name.
It also lets you use a typical business name without creating a formal legal entity (corporation, partnership, LLC, etc.). You can even open a business checking account and get a business phone listing for the name. For sole proprietors, this is the least expensive way to legally do business under a business name.
It allows a single legal entity (corporation, LLC, etc.) to operate multiple businesses without creating a new legal entity for each business. For example, if you are planning to operate a series of web sites, or a chain of bars, you might set up a corporation with a generic name, such as LVH Web Enterprises, Inc., or Neighborhood Bars, LLC, and then file an assumed name for each website or bar. Since there is significant expense in filing and maintaining a corporation, this helps control costs while still allowing you to expand your business.
How do you go about getting an assumed name or DBA?
In some U.S. states you register your assumed name with the Secretary of State or other state agency, but in most states, registration is handled at the county level, and each county may have different forms and fees for registering a name. Generally speaking, the process is fairly simple: you perform a search through their database to make sure the name is not already in use, then submit a simple form, along with the correct filing fee (anywhere from $10 to $50). Some states also require that you publish a notice in your local newspaper and submit an affidavit to show that you have fulfilled the publication requirement. Call your county clerk's office to find out the local fees and procedures in your area.
Laws vary significantly from country to country. For example, in the UK, there is no governmental filing process for the use of assumed names, but they are heavily regulated by the Business Names Act of 1985, which specifies where and how you must disclose business ownership. A private-sector initiative , The National Business Register, keeps track of current business names and help prevent duplication of names. Again, you'll have to check with your local authorities, as it would be impossible to cover every country here.
In addition to your own interests in filing an assumed name, keep in mind that the disclosure of actual business ownership is for consumer protection. Imagine doing business with a company, having a problem, going to file suit, and you can't find out who the actual owner is. You'd have to hire a private investigator.
Proper use of a fictitious business name can be a powerful branding tool at minimal cost. Take advantage of it: pick a great business name and then use it at every opportunity -- even every check you give and receive.