If it is organizational membership submit a scanned copy of a document showing that you are registered in your nation.
If this is not possible you may provide one of the following:
(a) A copy of the organization's organizing documents (articles of incorporation, constitution, and/or bylaws), or equivalent document; or
(b) A letter of explanation (signed by the office bearers) of why your organization is not registered properly
Attach proof of recent activities, such as a copy of a recent brochure or a copy of the most recent annual report. (A web site address for your organization will fulfill this requirement as well.)