How to find broken backlinks?

Hi everyone. I don't know if I'm writing my question in the right section, but I found too much unnecessary information on the inteet about this, so I hope some of you can help me understand it better.

How exactly do you find broken backlinks and fix them? I've seen a lot of tasks on Upwork for this request, and I'd like to lea how to do it. Is it something like links removed but left in google history?

A more explanatory answer would be appreciated. WordPress ...