A cloning item is a very flexible and well-designed feature of the Sitecore architecture, which allows us to reuse the content of an item or the whole content tree. It can be very useful for both single site and multisite instances for various purposes.
Let's consider a case where we have multiple sites hosted in a Sitecore environment, and we are creating and managing the same duplicate content for each individual site. Here, we will create source items on one site and clone them on another site.
For better understanding, this recipe is explained in the context of multiple sites, but it's not necessary for you to have multiple sites to work on it.