(iPad OS) Editing Visual copy?

There are two kinds of "visual copy." One kind, I would call "Faithlife Art." Those are essentially photographs, and uneditable. The other kind is "do it yourself." In that kind, there is the ability to change portions of the slid via the text boxes. I assume this is true on mobile as well, but am not in a position to check right now. 

What path did you take to stumble across this and/or create it?  

Unfortunately I don't own that resource to experiment with. I did have the text in the ACCS. When I created the slide on my Mac, I was able to replace the "reference" field with St. Jerome and move the reference box around on the screen. It may be that the specific slide you are using is an "author slide." If that is the case, then "Jerome" is what you get. You could try another style to see if you can get better results. 

Is your goal to simply figure it out on mobile, or to get the slide as you desire it? I can grab my iPad shortly to see what happens on mobile. 

I see that I misunderstood what you were trying to accomplish. I thought you wanted to move elements around (which is possible on desktop, not on mobile). The answer to your question is probably “yes.” If you tap the author field (Jerome), you should be able to change it to “St. Jerome: source reference here”