To make your own sign:
open this link after you log in to your tinkercad profile.
https://www.tinkercad.com/things/jh2OxYZt7Y0-enhanced-wifi-qr-code-sign
then click on tinker this.
select the sign, then select the ungroup button to separate the QR code from the sign.
after separation is made select the QR code object. then in the properties enter your WiFi information into into the Text box using this format: WIFI:S:ssid;T:WPA;P:password;;
test the code then select the both of the sign and the QR code and press the Group button to group them together.
now to export your custom WIFI QR Code select each object on it's own then click on export and make sure that (The selected shape) is selected under included, then press STL, repeat the same steps for the stand and there you go you downloaded your own custom made WIFI QR Code.
The author remixed this model.
made the old version myself but several mobiles couldn't read it so i adjusted the height of the QR-Code in order to be easier for all phones to detect and read the QR clearly.
also sliced the stand for a more low profile and steady look, it stands in a perfect shape, less filament used half the amount of the regular stand to be exact.