I still use outlook and its fab. Along with Word, good programs always have been.Win10 comes with Windows Mail and, despite your post, you can create folders and move mail between them. To do this, simply click on "More" at the bottom of the left hand menu (under the Folders section). At the top of the new screen, it will say "All Folders" followed by "+". Click the "+" and it will allow you to create a new folder of your choice. Then, go to the email you want to move, right-click it and select "Move". You can then choose your new folder and this will move your email across.
I'm thinking I've missed something here as the solution is really quite simple and I would have thought you'd have sussed it out, Peter. Maybe I've misunderstood and you're trying to do something different, I'm not sure. Anyway, for a better, more feature-packed email client, you could always just download the free Thunderbird. It's the best email client that I've used for years now.