Vipin,
On a desktop system, most USB/Bluetooth QR Code Readers will provide their input simply as a string of input from a Keyboard, so using CommCare's mobile QR code scanning capabilities won't be necessary.
If you want an app which functions equivalently on Mobile and Web, when structuring your forms I'd recommend following a pattern where each QR input looks like:
- input_qr: QR Code Scan
- input_manual: Text Entry
- input_normalized: Hidden Value
Where input_manual has a display condition where it is hidden when input_qr isn't blank and the "normalized" hidden value is set to whichever input isn't blank.
That will let you have a way to provide a QR scan which will work with either the mobile phone camera, or an external keyboard driven QR reader on web apps.
-Clayton