Donate
There should be a description here about what kinds of donations the ELRRHS accepts - documents, paperwork, etc. for the archives, and a process to do that (email first? call first? or just shove it in a box and mail it to Avoca?).
There should also be a link to make financial donations online. Like membership, this should be done through Zeffy, a non-profit organization that specializes in memberships and donations for other non-profits. Notably, Zeffy does NOT charge any credit card processing fees for these services.
You can view an example of a Zeffy donation box, integrated into a Squarespace website, at: https://www.pjmuseum.org/donate
Make sure to include some kind of description about 501c3 status, donations being tax-deductible, something about tax advisors, etc. And also put something about estate planning, bequeathments, etc. for both financial and material/archival donations.