When you save a document, it saves the view definitions and properties of all of the plotted objects within each of those views. It also saves the paths to many ancillary files, such as the primary database, external data files, image files, CAD files, and shapefiles. If you would like to archive a project or move a project from computer to another then you will need to move both the document and these ancillary files. EnviroInsite's Zip Project functionality simplifies this process by loading the document file and all of these ancillary files into one zip file. When you unzip the files, you should keep them in the same folder as the document or in subfolders of the file that contains the document so that EnviroInsite will find these files when you load the new document.
To zip a project select File -> Zip Project from the main menu.