This guide includes high-level information about starting a nonprofit and refers to other resources that go into more depth. This page includes forms, fees, and instructions for all domestic business entities, foreign and domestic Registered Agents, and Washington Trademarks.We've compiled the internet's largest list of FREE nonprofit templates, worksheets, and guides you can use for everything your organization might need. Here, you can find out how to register a nonprofit in the state of Washington, the annual filing requirements for a nonprofit in Washington, and more. This guide covers the required filings to maintain a nonprofit corporation in Washington. Only certain organizations are eligible to file Form 1023-EZ (see Who Can File This Form, below). Note. How to Apply for Nonprofit Rates. As mentioned above, the first step is to fill out Postal Service Form 3624, which is available online. Caution: This handbook contains information about the laws impacting nonprofit organizations in Washington. Most organizations seeking exemption from federal income tax under section 501(c)(3) are required to complete and submit an application.