The iOS and Android barcode apps are designed to be used when you don’t have access to a physical license/barcode scanner. This is useful for users who are checking in remotely with their smartphone or tablet.
Simply click the download link on the config page to download the app from the app store. Once you have the app downloaded, be sure to open, navigate to Settings, and make sure PDF417 is enabled. This is the type of barcode that Drivers Licenses have.