It's a pack of different tools and components that you will be able to install to vary the aspect to the optimum point of each user. It includes a window manager, a desktop manager to control the desktop wallpaper and the appearance of the root menu, panel, a session manager, a files manager and a configuration manager.
The software is even capable of expanding its possibilities thanks to its applications and plug-ins... It's a good moment to download Xfce for free and see if it's possible to modify the appearance of the operating systems based on Unix in an aesthetic and functional way. Anything to try to improve its aspect.