All businesses in Washington are required to be registered with the Washington State Department of Revenue.  Details and instructions are here: Open a business | Washington Department of Revenue

Once your business is registered with the State, you will need an additional license to operate within the Coupeville town limits. Chapter 5.40 of the Coupeville Municipal Code includes the various licenses required.  There are applicable exemptions listed within each category.

Business License Ordinance (802)

All businesses, including Home Occupation businesses and Non-resident businesses coming into Coupeville to do business, are required to get a Coupeville Business License. You can apply for your license here: https://dor.wa.gov/manage-business/city-endorsements/coupeville

Those exempt from a Coupeville Business License include but are not limited to: Festival and Farmers Market vendors, any tax-exempt non-profit, credit unions, and more. See Coupeville Town Code 5.40.060 for a full list of exemptions. Non-resident businesses coming to Coupeville to do less than $5,000 in business are required to get a business license but will be charged a $0.00 fee.