Paste a web address and download its QR code. Your link never leaves this computer.
Preview
Scan the code with your phone once before printing.
When an address starts with http:// or https:// phones recognize it as a link for sure. Some cameras may show an address without it as plain text.
PNG is good for sharing as an image and for putting in documents. SVG is a vector, so it stays sharp however large you print it.
A short address makes a less dense, easier-to-read code. For very long addresses it helps to shorten the link first.