Recently Microsoft made an update to SharePoint to help with allowing mobile to quickly access documents from SharePoint online. They added the ability to access a QR Code that will take you directly to the select document.
You can access the QR Code by going into the Open Menu (ellipsis) associated to a document within the SharePoint online environment. Within the menu you will now see a Mobile icon that will allow you to access the QR Code.
Once this has been selected you will receive the QR Code link to the document. This information can then be embedded and distributed as needed.
If you have not heard, Microsoft is leading with making changes to the SharePoint online environment before releasing them to on-premise. So it will be interesting if this is one of those features that will eventually be released.