What a QR code stores
A QR code is just an image that encodes text — most often a web link, but also WiFi credentials, a phone number, or a contact card (vCard). A phone camera reads the pattern and acts on it: opening the link, joining the network, or saving the contact.
Static vs dynamic — read this first
A static QR code has the data baked into the image, so it works forever and needs no service behind it. A dynamic QR code points to a redirect owned by a provider — handy for editable links and scan tracking, but it can stop working if that provider shuts the link down or starts charging. For a code you print once and rely on, prefer static.
How to make one
Open a QR generator, choose the type (URL, WiFi, or contact), enter your details, and download the image. A good tool produces a static code as a PNG or SVG you own outright — no account and no expiry. Use SVG if you will print it large, since vectors stay sharp at any size.
Make sure it scans
Keep good contrast (dark code on a light background), leave the quiet margin around it, and do not shrink it too small for the scan distance. If you add a logo in the middle, test it on a couple of phones before printing in bulk.