Have a technical question you can't find the answer to in FAQ's? Ask it here. Game problem questions that do NOT pertain to things like training advice, what would my horse do well in, how much is it worth.
Those are placed on a horse when it joins the club the banner is associated with. So my horse has "Zimified" banner on it because it was entered into Zimmy's club that has the banner.
I believe you put the html code where the club's name would normally be typed. But it might be the image code or just the link to the image, so you might have to kind of play with it a little