King County is large, so there are two King County Superior Court locations:
One is in downtown Seattle:
The other location is in Kent:
The Snohomish County Superior Courthouse is located in Everett
DCS is an administrative agency. Any party can opt to have an order of child support collected and enforced through DCS. The DCS website is where you can learn about child support obligations and set up an online child support account so you can do things like make electronic payments, check payment status, and get payment history.
Washington State has minimum mandatory forms for most legal documents.