State Diagram text

While working through the Object-oriented Technology book, p206 shows some text that sort of looks like a state but I can’t recreate it. See the attached image: it is the text next to the pencil tip beginning with ‘transaction success’ and then other text separated by a solid line.

I think this is a good way to anotate drawings but I’m at a loss as to how to do this.
StateDiagr.JPG