There are a ton of apps on the app stores for QR scanning, but these are often either low quality or kind of tacky. Thankfully, a lot of manufacturers have started including automatic QR scanning right in their stock camera apps. Samsung included.
So, here's how you scan a QR code with the latest-and-greatest Galaxy Note 20 phones.
1. Open camera Settings and make sure that QR scanning is enabled
2. Get close and point the camera to the QR code
3. If it's a website, you can tap the little arrow to open it up automatically. If it's any type of text, tapping on it will copy it within a new note in Samsung Notes.