QR codes are just smart little data blocks. You need a QR reader to unlock this data. These are annoying because you usually have to download a third-party app and some of these apps are shady. Fortunately, your Samsung Galaxy with One UI has a built-in QR scanner.
Scan QR codes with your Galaxy
Open the stock camera app of your Samsung One UI device. Find a QR code that you want to scan and point the camera at the QR code. A pop-up appears – tap to deep link or visit a URL. You now have the most convenient QR code reader on your device.
You can turn this feature on or off in the camera settings. If the QR reader is not working and your device is running Android 9.0 or higher (one user interface), make sure the setting is turned on by swiping to the right in your camera app and going to settings. At the top you can enable the "Scan QR codes" switch to enable scanning.