Printing a QR code with default config works via the Print qr2wiki code (default config) link in the top right action menu of your page. The default config consists of the the current page title as header and the URL of the page as footer.
Downloading a customized QR code - VERSION 2.0.0
To download a customized QR code click on the button qr2wiki on the top right corner of your page.
This will open a dialog where you can customize the header and footer text of the QR code. Then you just need to click Download QR code.