Unmarried parties who wish to determine the parentage of the father, establish a residential schedule / parenting plan, or set child support, may do so in this action. There are many forms, but in a simple case the father has signed a paternity affidavit at the hospital which should be on file with Washington State Department of Health Vital Statistics. You can call Olympia to check: 1-360-236-4300. You will need to include a Certified Copy of the Paternity Affidavit in your paternity action, but if you do not have a copy you may order one for about $35. by calling 1-360-236-4335. The filing fee in King County WA is $280, but you may be eligible for a waiver based upon financial need. Once filed, you will have an opportunity to agree to a Parenting Plan, or the simpler Residential Schedule, in addition to child support.