https://www.cnet.com/news/galaxy-fold-vs-huawei-mate-x-battle-of-the-foldable-phones/

Does your phone fold in or out? Samsung's Galaxy Fold takes the form of a book, with its largest screen on the inside, protected by the outer "cover." Except in this case, one of the "covers" has a screen on it. 

Huawei takes the opposite approach, with the screen hugging the frame. The advantage here is that you have one screen that can act like three, depending on how you hold the phone.