Common app additional information

what type of things go into the additional information portion of the common app? Is it recommended to fill it out?

I certainly wouldn’t put anything in there that 1) you’ve already mentioned elsewhere, and 2) aren’t of SIGNIFICANT info. My son placed a resume style info of his most significant accomplishments that he wasn’t able to list elsewhere. Some folks would disagree with placing a resume there, but the 7 schools that he was admitted to didn’t seem to mind. Use that space carefully, though, i.e., don’t use it just because you don’t like to waste empty space.