The desktop is simply “what you see on the screen”. A desktop environment provides the framework of the desktop and includes the underlying structure (things you don’t see) and the interactive components like menus and toolbars as well as programs like the file manager and image viewer. Windows and MacOS are examples of desktop environments, each with their own distinct characteristics. Unlike these operating systems, Linux provides the choice of many options instead of one.
Depending on the distribution, there may be one or more choices available. The option of desktop can depend on which version of a distribution you download or, in some cases, you may have a choice when installing. Understanding the choices available and what you prefer in terms of layout and capabilities can help you decide which distribution, or at least which version of a distribution, is right for you.
The desktop environmnts shown below are presented in random order. Any of these are a good option for new users. Each one is well supported, provides users with tools to manage their system and are generally very stable and easy to use. The particular approach to how it behaves can vary quite a bit so you’ll want to look at the option and try a few different ones to see what suits you best.