A DBA ("doing business as," also called a fictitious business name or trade name) lets a business or individual operate under a name different from their legal name — without creating a separate legal entity the way forming an LLC does.
Who typically needs one
Sole proprietors operating under a business name instead of their own legal name, and LLCs or corporations doing business under a brand name different from their registered legal name, generally need to file a DBA to do so legally.
It doesn't provide liability protection
A common misunderstanding is that filing a DBA offers the same liability protection as forming an LLC — it doesn't. A sole proprietor with a DBA is still personally liable for the business's debts and obligations exactly as they would be without one.
Filing requirements vary by state and county
Some states handle DBA filings at the state level, others at the county level, and publication requirements (announcing the new name in a local newspaper) still apply in some jurisdictions — a detail easy to miss if you're filing based on another state's process.
It doesn't protect the name from being used by others
Filing a DBA doesn't function like a trademark — it doesn't stop another business from using a similar name in a way that could confuse customers. Businesses relying on their name as a real asset generally need trademark protection in addition to, not instead of, a DBA filing.