You could easily convert your WiFi credentials into a QR Code and paste it on your fridge. Your guests just have to point their smart phone cameras to the QR code and it will get them connected to your WiFi network
NOTE: The QR Code is generated fully on the client side. Which means no data is transmitted to the Server. Which also means the QR Code Generator will work offline. You can disable your WiFi internet and it should still generate a QR Code for you!
https://modemly.com/qrcode
Hittly