Use this qr code wordpress plugin to create a qr code on any site of your WordPress installation. Content can be any text or the current URL of the site where it is embeded.
How to use it:
Use the shortcode [qr-code] within your site to generate a qr code including the URL of the current site
Bijon Krishna Bairagi
“I create useful free microsites!”
(https://bijonkrishnabairagi.blogspot.com/” Free qr code online generator”)