What should the QR contain?
Members can scan this with any phone camera to open the link instantly.
QRs can hold a few thousand characters; if your text is long the code gets denser.
Most modern phones auto-join when they scan a Wi-Fi QR. Print one and stick it near the front desk.
Scanning starts a call (or pre-fills the dialer). Include the country code.
Higher error-correction lets damaged or partly-covered QRs still scan, at the cost of a denser code. M is fine for most uses.