Wash. Rev. Code § 36.71.020
Every peddler, before commencing business in any county of the state, shall apply in writing and under oath to the appropriate county official of the county in which he or she proposes to operate for a county license. The application must state the names and residences of the owners or parties in whose interest the business is to be conducted. The applicant at the same time shall file a true statement under oath of the quantity and value of the stock of goods, wares, and merchandise that is in the county for sale or to be kept or exposed for sale in the county, make a special deposit of five hundred dollars, and pay the county license fee as may be fixed under the authority of RCW 36.32.120(3).
The appropriate county official shall thereupon issue to the applicant a peddler's license, authorizing him or her to do business in the county for the term of one year from the date thereof. Every county license shall contain a copy of the application therefor, shall not be transferable, and shall not authorize more than one person to sell goods as a peddler, either by agent or clerk, or in any other way than his or her own proper person.
RCW 36.71.020