Hello,
We have been using GP Premium with GP Block pro. We want to show different info with coloured boxes inside articles. We know it is very easy to do with block editor but we are using classic editor as our team is on that.
If you’re using the Classic Editor, you can probably add it manually through custom HTML. Just give it a unique class so you can have one CSS for all your info boxes. Providing this sort of custom support would be out of our scope though.
Another route is to look for an infobox plugin that has a Shortcode. It might be good to ask for recommendations in our Facebook group as well for this: https://www.facebook.com/groups/1113359788719597