iphones can scan such qr code to join the network, just point at it with the camera and hud will hover with the ssid. then click on it.

i created one out of plastic beads the other year with my wife

this is what i used:

    qrencode -s 6 -l H -o "wifi.png" "WIFI:S:SSID;T:WPA;P:PASSWORD;;"

https://fukuchi.org/works/qrencode/