You must register a trade name, or “doing business as” name, per RCW 19.80.10 for:
A Sole Proprietor or Partnership using a name other than the full legal name of the owner or owners.
A Corporation, Limited Partnership, or Limited Liability Company operating under a name other than the name registered with the Office of the Secretary of State.
Any business name you are using that is not your full legal name.
Registering your trade name does not protect the name from use by others. A business can register an unlimited number of trade names.
A trade name will remain registered indefinitely until the owner requests that it be canceled. There is no charge for canceling a trade name.
If you also want to file a trademark or service mark, you may want to consult an attorney. If your business activities will extend beyond Washington State, it may be to your benefit to file for a trademark with the U.S. Patent and Trademark Office. If your business activities will stay within Washington, it may be to your benefit to file for a trademark with the Secretary of State.
Find out if a name is already in use
Register a trade name
File a Business License Application online with My DOR.
Pay the $5 fee for each trade name registered and the Business License Application processing fee (non-refundable), see instructions on how to determine your processing fee.
Cancel a trade name
See also the Trade Name Registration- Business Bulletin
How to apply
Add a state endorsement to your business
Add a city license to your business
Apply for a new business license
Setting up your business licensing and tax account
How to add a city license endorsement
Complete the following and mail to:
Business Licensing Service
P.O. Box 9034
Olympia, WA 98507-9034
Business License Application