How can you create such a magical "Add to Favorites" button?

Question

Joomla

Hello, I would like to use on my site such a button "Add to favorites" (you can also with a heart, but I think I'll find it) and then from "Favorites" you could remove it if you don't need it anymore, IMPORTANT for unauthorized users I don't have registration. Here's how on this site: https://okeyimobil.md/ru/properties/casa-criuleni/...
Somewhere I read that you can use Widgetkit, but I don't see such an implementation there.