The Moto X4 boots Android Nougat - time was not enough to get an Oreo-based ROM up and running. As is usually the case with Motos, it's a very minimalist user interface, very close to stock Android with only a few extra touches here and there.
Motorola Moto X4 review
Starting off with the launcher, it looks a lot like the original Pixel's launcher, complete with a swipe-up app-drawer. You can tap and hold the white tab on the right of the drawer to scroll through apps by letter. The most frequently used apps are on the top row.
The Moto launcher also supports long press on apps that have it implemented. You can then drag the functions out as independent shortcuts for quick access as well. 