You can send physical mail to Erin at:
PO Box 178
Concord, NH 03302
If you’d like a signed bookmark and stickers, send a self addressed stamped envelope (SASE) to: Erin Bowman, P.O. Box 178, Concord, NH 03302.
Make sure your envelope is at least 8 inches long, or the bookmark will not fit without being folded. A Forever stamp (foreign or domestic depending on your location) is strongly recommended.
If you own a digital copy of any of Erin’s books, you can request a signature via Authorgraph. If you’re interested in purchasing a signed physical book, you can order through her local indie, Gibson’s Bookstore.