There are many ways to support the PCT in Washington and hikers who enjoy it. This could be anything from sharing trail reports and updating the FarOut app with water locations to volunteering to repair the trail itself. Everyone on the trail can support it by practicing leave-no-trace (LNT) virtues.

Trail Maintenance

There are three regional groups in Washington.
You can volunteer for any of them using the PCTA Connect site.

PCTA North 350 Blades

Supports 350 miles of trail from Chinook Pass to the Northern Terminus.
Facebook: North 350 Blades
Email at PCTA

PCTA White Pass Chapter

Supports 70 miles of trail from Midway to Chinook Pass.
Facebook: White pass Chapter
Email at PCTA

PCTA Mount Hood Chapter

Supports 214 miles of trail from Bridge of the Gods to Midway (and parts of Oregon).
Facebook: Mount Hood Chapter
Email at PCTA

Washington Trails Association

Not directly associated with the PCTA, the WTA is a state-wide organization that supports public use of trails and public lands in many ways including coordinating volunteer trail maintenance that sometimes includes the PCT. Their website allows sharing trip reports that are extremely valuable for planning hikes.
WTA Volunteer

Lodging

I'm waiting to hear from the owners of various hiker hostels regarding what they would like said about them here and how they want people to volunteer. I will update this page after I hear from them.

Trail Magic

Delivering "trail magic" as a "trail angel" covers a wide variety of hiker support activities including rides to/from trailheads, feeding hikers, delivering needed supplies, and more.
The PCT Washington Trail Angels page on Facebook is where you can match your ability to help with the current needs of hikers.