Take the new version as an example:
Open the QQ browser and click the "Scan QR code" icon on the browser home page to open the QR code outside the camera scanning device or read the QR code in the photo album for scanning.
Open the QQ browser. When you are browsing the webpage, click the icon on the right side of the search box to open the extension panel, and then click "Generate QR code" inside to share your webpage through the QR code.
Long press the QR code picture in the webpage, and the option will be opened. Click "Recognize QR code" to scan the QR code in the webpage.
I wish you a happy life. I hope my answer can solve your problem.