Once upon a time the usual thing to get OK'd to rent a van (e.g. for students who are moving house) is you rock up to the rental place with the legal documents showing you're entitled to drive. You're relying on the fact that the person renting you a van doesn't much care and isn't keeping the exact details from those documents.
But although you can do this today, obviously the documents get scanned into a permanent data repository, so, that's not great. But, the UK government added a site so you can prove you're you, and get codes, which for a limited period show someone that yup, this person is legal to drive and so on.
They do this for right to work too. Although, annoyingly only for foreigners. If you're a citizen, you can't prove right to work this way, you need to be like "Look, I'm a citizen, here's proof" to your employer. But if you are foreign you can just go "Check this URL, your government says I'm entitled to work here" and they needn't know whether that's because your husband is a "Cultural Attaché" to the Russian Embassy, or you've got special refugee status, or you're actually an Italian and you just speak and look Russian for some reason, just that you're entitled to work here.