Importing into KiCad

Use the transparent SVG that was generated. In the PCB Editor go to File → Import → Graphics or Shift+Ctrl+F, find the saved transparent SVG in the dialog, choose the layer, and you’re done.

Watch out for scams

When I went looking for a QR code generator to use in KiCad there were thousands of sites offering that. Many were scams — some required payment to generate, others watermarked the result with their logo, and worse, some were free but the QR code pointed to their site, which then redirected to your intended URL.