Starting on May 18, all King County residents are directed to wear a cloth face covering in most public settings, such as indoor public spaces or spaces where it is difficult to maintain six feet of physical distancing. Face coverings can include: cloth face masks, scarves or bandanas. Clear masks or face shields are also an option. There are exceptions for some individuals who will not need to wear a cloth face covering. 

Additional information  

Public Health–Seattle & King County  
CDC: How to make a homemade face cloth covering