Viewports control which objects are displayed on screen and when outputting a drawing.
When working in model space you draw geometry in tile viewports (referred to as Viewport objects in ActiveX Automation). You can display one or several different viewports at a time. If several tiled viewports are displayed, editing in one viewport affects all other viewports. However, you can set magnification, viewpoint, grid, and snap settings individually for each viewport.
In paper space, you work in floating paper space viewports (referred to as PViewport objects in ActiveX Automation) to contain different views of your model. Floating viewports are treated as objects you can move, resize, and shape to create a suitable layout. You also can draw objects, such as title blocks or annotations, directly in the paper space view without affecting the model itself.