Confirmation user hook

Hi,
I need to know when a user confirms in the welcome email, because I have to update other user information (user meta).
I have seen the documentation, to look for some action or filter. But I didn’t find anything specific or how they should be used.

Maybe “getSubscriber” is what I need? How am I supposed to use it?

What I need is an action that tells me that a user (user id) has confirmed and through this, I update the data.

Thanks so much