I wish more people would do this, it makes access to Wifi much easier: https://www.wikihow.com/Make-a-QR-Code-to-Share-Your-WiFi-Password
Update: If you have a BT HomeHub, the QR code you need is already available in the administration pages:
I wish more people would do this, it makes access to Wifi much easier: https://www.wikihow.com/Make-a-QR-Code-to-Share-Your-WiFi-Password
Update: If you have a BT HomeHub, the QR code you need is already available in the administration pages: