Most modern smarphones will automatically detect a QR Code when you scan it with your camera like you are taking a photo.
For example, on my Android phone:
- I open the phones Camera app that I use to take photos.
- I then point my camera at the QR Code I want to scan.
- My phone detects it has seen a QR Code and will show on the screen a button for me to tap to convert the QR Code / open the link.
You can also download a QR Code reader or a Barcode Reader from your phones app store.