Not a bug just a question

Where do I go to give helpful suggestions? I look through the minecraft market place. Before buying a world, I want to know where do the worlds tell you if it's flat or infinite before buying them. I spent lots of minecoins on a world that was flat, with boarders. I would have liked it better if it was infinite. If there is no way to tell before buying it, I suggest that you have it in the descriptions before we buy worlds so we will know if there is contiuous space or not.