To save a map, click Survey > Save from the top menu bar. This saves the entire project file and all maps associated with it (saved NetSpot project files have a .netspd file extension).
To export a copy of just the map once you are done drawing it (but BEFORE you have started a scan), click the Export button on the top-right of the toolbar.
To export a copy of the map AFTER you are done scanning. Click Survey > Zone > Export Zone Map.
You can also export the visualization heatmaps to PDF. Simply click the Export button above the map.