Paper: 110 lb cardstock (199 gsm) in white, cream, or ivory. Standard 8.5″ × 11″ sheets. Available at Staples, FedEx Office, or Amazon.
Print: Open print dialog → select Double-Sided (Duplex) → Flip on Long Edge. Scale 100%, quality Best, US Letter. Each card uses two pages — Side A on front, Side B on back.
No duplex? Print odd pages first (Side A), flip the stack, then print even pages (Side B). Or take the PDF to any print shop.
Cut & fold: Trim top and bottom margins at the crop marks → fold in half along the center line, right edge to left → "Thank You" cover faces out, open like a book. Finished size: 4.25″ × 5.5″ (A2).
Envelopes: Search "A2 envelopes" on Amazon — 50-pack runs $8–12. Size 4⅜″ × 5¾″.