QR Code vs Link: What's the Difference?
A QR code is a visual container for a link (or other data) — scanning it does exactly the same thing as clicking the link directly. Any phone's camera app can decode a QR code back into the URL it holds, which is how you'd "convert" a code into a clickable link.
There's no meaningful technical difference between visiting a URL by typing it, clicking it, or scanning a QR code that contains it — all three end at the same destination. The QR code is just a physical-to-digital bridge: a way to hand someone a link when there's no way to type or click one, like on a printed sign or a product package.
To go the other direction — reading what URL a QR code contains without opening it — point any modern phone's camera at it; most show a preview of the destination link before you tap to open it.