In general, passes and permits are concerned when you decide to go hiking in the Northwest. It is up to what kind of places you are going to visit: national parks, service lands, state public lands, or so.
For the national forest recreation day pass and epass, you can purchase online or at the National Forest offices and the Visitor Information Center close to your hiking trailhead.
You can get an annual pass at all Forest fee sites in Oregon and Washington for Northwest Forest Pass. Otherwise, you can purchase one at the National Forest offices.