We use me-qr.com to generate the QR codes, though my computer consultant suggested https://www.qr-code-generator.com.
We put the appliance manuals in a free Google website, then create a QR code that links to the manual. The QR code is printed on a sticker [@PitonView told me about this] that’s applied to the appliance. So although we have the QR codes in the House Manual they’re also on the appliances (or soon will be) so the guest can view the QR code with their smart phone and then immediately view the appliance manual.
We have instructions for everything in our House Manual but provide QR-code links in the House Manual, and soon on the appliances themselves, to the manuals themselves.
I attached one here for a draft of our cleaning checklist: How Would You Suggest This Draft of an Airbnb Cleaning Checklist Be Improved?