QR codes are those square ‘barcodes’ in which you can encode either a URL or other things, for example, text. Although it has been rumoured that these codes are not used much by visitors, in fact (as at 2018 at least) smartphone camera apps increasingly autmatically recognise these codes so there is low friction to using them now.
iMuse has used them as a fun way for children to get the next clue in a detective trail, and they can be useful in a heritage site for example to show further information about a site.
There are many online services which offer to make QR codes for you. We caution against (at least some of) these as they act as an intermediate step in sending a visitor to your site, not only collecting information as they go but also risking your sustainability as they may withdraw their forwarding service without warning. Luckily you can create a QR code which does not contain any additional risks like these.
If you Try it you can create a QR Code containing the text or URL of your choice. For longterm sustainability, you can copy the HTML code and have it on your own computer for future use.