That’s the long link inside the QR code (https://pracproof.co.za/verify#…) — paste it from an email, WhatsApp or a QR-scanner app. The short code printed on the document (like 53F6-49FD) can’t be checked by itself; after a scan it’s shown so you can match it against the paper.
The signature check runs on your device; the QR contents are not uploaded by this check. A valid result confirms that the signed QR details pass the signature check. Compare them with the document: this does not check the entire PDF or prove the prescriber’s identity. Check registration and contact the practice independently when needed.