Business Registered (Legal) Name
Every business must have a legal name, which is registered through the state and also through the process of obtaining a Tax ID or Employer ID number. Registering a business name with your state may involve simply filing a name registration request or filing an application as a corporation or limited liability company or other business type (the name registration is included in the application). Your registered business name is the one used for taxes and legal matters.
For example, Dave Holtan forms a limited liability company to sell books on the Internet. The name of the LLC is Holtan Enterprises and that is the name he uses on the EIN application and the Articles of Organization.
A trade name is the name the business uses for advertising and trade purposes, with clients, vendors, customers, and the public. Its trade name is the name the general public sees, on signs, on the website, on advertisements. The business trade name may be different from the registered name. Holtan Enterprises, for example, uses "Dave's Books" as its trade name.
Filing a Fictitious Name (D/B/A) Application
If you are using a different trade name from the registered name of the business, the public has a right to know who is actually running the company. So you must file a fictitious name statement (sometimes called a d/b/a statement, for "doing business as") with your county. This statement is posted in the newspaper and becomes public record, letting everyone know that your trade name is connected to another legal name for the business. Sometimes on legal documents the two names are connected; for example, "Holtan Enterprises, d/b/a Dave's Books." Dave's Books is the trade name, and it has filed a fictitious name statement connecting that name with Holtan Enterprises. If the registered business name and the name you are doing business as are the same, you do not need to file a fictitious name statement
Trademarks and Business Names
A trademark asserts ownership of a business name, along with a logo and maybe a catchphrase, as a unit, or as a "brand," letting others know that you have the sole right to that name. Even if you don't officially register your trademark, you may still want to use the "TM" or "SM" designation as a form of public notice of your ownership. If Dave had an artist create a logo using "Dave's Books" and a graphic, he could trademark that logo to keep others from using it.