DBA is an abbreviation for "doing business as." Certain jurisdictions may also use the terms "fictitious business name," "trade name," or "assumed name." DBA registration is necessary if your business operates under a name other than its legal name.
For a corporation, LLC, or other state-registered entity, the legal name is the name on the filed articles so, if you want your corporation or LLC wants to operate under a different name, you must file a DBA registration.
For all other business structures, such as a sole proprietorship or partnership, the legal name is the personal name of the business owner or owners. Conducting business and opening a bank account under any name other than your legal business name is only possible after fulfilling your state's DBA filing requirement.