You give your details to various companies and organisations, when you buy something you give your address and email and more. All you can do is hope that they will look after them. But sometimes these organisations are hacked or carelessly lose your details. There is not much you can do about it.
But if nothing else you can sign up to have i been pwned. They look at the data in known data breaches and tell you if you are someone affected. It’s free and quick to join.
Confused by the name? In online gaming, if another player beats you, they now “pwn” you - you have been pwned. It is a mistyping from “own”, while online gaming you often type fast and hit the wrong key; “O” is next to “P”.