A view window is simply a window in which the content of a file is loaded. When you open Ansys Viewer for the first time, it has one view window displayed. You can display up to four view windows at the same time, and load a different file into each one.
A view is like a scene that provides a different perspective of an object. For most Ansys applications that are capable of generating .avz files, views that are associated with a simulation file are captured in the generated .avz file, and will therefore be available in Ansys Viewer.
You can manage view windows and views using the View Manager.