Please disregard my comment! I said some stupid stuff because I didn't understand the context of the question. Sorry about that!

I'm not sure how obvious would it sound but Polygon uses LaTeX as formatting tool. You should check out its guides.

Can't help you with bold, italic and that kind of stuff as I've never tried it... Though you can put images with \includegraphics{image.png} and picture itself you should insert into "statement resourse files" thingy in the bottom of statement page.

bold, italic: https://www.sharelatex.com/learn/Bold,_italics_and_underlining

bullet/enumerate list: https://en.wikibooks.org/wiki/LaTeX/List_Structures

I use the following to add a picture in the center/middle of the page (like in 643B - Bear and Two Paths):

\begin{center}
\includegraphics{two-paths2.png}
\end{center}