Most modern phones have QR code reading built into their camera app now. If you have any reasonably recent iPhone or recent Android phone you will be able to read a QR code just by opening your camera app and holding it up to the QR code you see, keeping it reasonably still. You will then see a prompt to open the link given.
You are probably used to it right now checking in to many venues for COVID safety — this is just the same!
If your phone is older or doesn’t seem to have QR codes built in, you can usually find a free QR code reading app. YOu can find some suggestions on how this works at this article. Or just look up “QR Code” on your phone app store (usually “App Store” or “Google Play Store”).