Let's say we have more than 10 pages and groups on Facebook. When you share the same post on all those pages and groups, Facebook might consider posts as duplicated posts, and you might get a warning from Facebook.

By customizing the link, the ending of each link gets random symbols.

As a result, the post becomes unique, and you can share the same post as many pages or groups as you want.

The feature also allows you to define and type your custom post URL using specific keywords. You might need it if you want to share a different URL than your post URL.