When I set up lead ads recently, the share option was not there. Did I do something wrong or did that change, and are the shares important?

I've run lead ads before and I noticed that sometimes they are shareable. In other words, people can click share and when the program started, they shared amongst friends. They shared and we were able to get more leads that way, just from the shares. I noticed this time when I set up the lead ads, the share option was not there...