In europe we have a kind of mini passport, called person id. Which only works in your own country and other shengen countries. It’s nearly the same cost as a passport (at least in my municipality)

You are required to have a passport (or id) with you (as in, that’s what the law says). Even in your own country. But in your own country a drivers license is usually also sufficient.

But in practice you will almost never be asked to show any of those. In your own country, nor abroad.