It would be nice if there was a QR Code node that could generate visually appealing QR Codes or any QR Codes at all. See the following for inspiration:
There should be both an encode and a decode node.
I encode JSON in QR Codes prior to printing a document and later extract it from a scanned PDF of the document.
Other documents will have a QR Code that is intended to be scanned by the recipient using their phone.
The types of data that can be encoded are set out at https://www.qrcode-monkey.com/.