The default icon for a required field is an eye, and I wanted a red star. It wasn’t hard and this following article got me started.
Start by going into the Element’s properties by going to “Elements” and then double-click on the element you want to add the requirement. This assume you have a validation on element already if not click the Add button to add one. I used the “notempty” plugin. At the bottom you will see a field for “icon”. It pulls from the “/media/com_fabrik/images” folder and I choose one of the .png files that was there, so in the field I just added the text “notempty.png”.
I hope this helps someone else out there.