What the code actually contains
A WiFi code is plain text in a documented format: WIFI:T:WPA;S:MyNetwork;P:hunter2;H:false;; where T is the security type, S the SSID, P the password and H whether the network is hidden. There is no encryption and no lookup — the password is sitting in the symbol in readable form, which is exactly why the code works without an internet connection.
That format is the reason semicolons, commas, colons and backslashes in a password have to be escaped with a backslash. This generator handles that for you, which matters more than it sounds: a mis-escaped password produces a code that scans cleanly and then silently fails to connect.
Which phones support it, and which do not
iOS has recognised WiFi codes in the built-in Camera app since iOS 11, and Android since version 10 — both show a join prompt rather than a link. Android additionally goes the other way: in the WiFi settings, the Share button produces a code for the network you are already on, which is often faster than typing the password into this form.
Laptops are the gap. Windows and macOS do not scan WiFi codes from the camera, so a code on a meeting-room wall helps phones and tablets and does nothing for a visitor with a laptop. Keep the written password available as well.
Hidden networks and the security type
If the SSID is not broadcast, tick the hidden option. It sets H:true, which tells the phone to probe for the network by name instead of waiting to see it in a scan — without that flag, a code for a hidden network appears to do nothing at all.
Pick WPA for anything modern; the same setting covers WPA2 and WPA3. WEP exists in the format for legacy equipment and should be treated as a signal to replace the router rather than as a working option. For an open network with no password, choose the no-password option so the phone does not sit waiting for a credential that will never come.
Where to put a printed code — and where not to
Cafés, waiting rooms, holiday rentals and meeting rooms are the natural fit, because the alternative is reading a 16-character password aloud. Laminate it if it will be handled; a code with a torn corner may still scan thanks to error correction, but a missing corner marker will not.
Treat the printed code as equivalent to the password written out, because that is what it is. Anyone who photographs it keeps access until the password changes. Put guests on a guest network, and if your router supports it, isolate that network from the devices you actually care about.