Word 2016 - Text next to arrows that point to text boxes

Word 2016/Win10:

Hi,
Please see the attached, redacted Word doc. I need to insert (in very small orange font) the word "DogID" below the horizontal arrow which point from Cats to Dogs. (I know it's a tight fit, but that's not my question. :) )

I tried to copy the instance of DogID on the left of the page, but I can't. In fact, it seems like it's tied into the adjacent text box. Unfortunately, it's been a while since I created this doc, and I can't recall how I entered "DogID" in the first place.

From this doc, can someone deduce how I entered "DogID" and how I'd get another instance of it below the horizontal arrow?

Thanks!
Steve
RedactedTextNexttoArrowsAndTextBoxe.docx