Use a static QR code when the destination will never change — a Wi-Fi password, a plain link, a one-off message. It's free forever and doesn't need an account. Use a dynamic QR code when you want to edit the content later or see how many people scanned it — perfect for menus, business pages, or anything you might update after it's already printed. Either way, the printed code itself never has to change — only what's behind it does.