Sounds like the BankID system they have in Norway and Denmark (maybe also Sweden?).
The way it works in Norway is that, once you have a bank account (which means you had to identify yourself using passport or similar) you can get a BankID which allows you to log in to a lot of online services (health, tax, employment, etc) without having to do anything else.
[0] https://feber.se/samhalle/regeringen-vill-ha-en-statlig-e-le...