Direct answer: Get your annual meeting notice to every member by uploading the notice and your member list to USMail.ai, checking the on-screen copy and approving it; we print and mail it First-Class, Certified or Priority. Your bylaws and state co-op law set the notice rules, so confirm them with counsel first.
Letters starting at $1.15, postage included. For a one-page, single-sided, black-and-white First-Class letter.