There are two types of project/design files in Xilica Designer: .pjxml and .sxml. 

 .pjxml: Xilica Designer project file.

This is the primary type of project file. It constitutes the entire project design, including schematics/programming for all DSP devices and controllers. To save a .pjxml file, simply File > Save or Save As.

 When saving files, best practice dictates the following format:
(ProjectName)_(SoftwareVersion)_(FileVersionNumber)_(LastUpdateDate)

.sxml: Device schematic design file:

This type of file constitutes schematic/programming for a single device only. 
There are 2 ways a .sxml file can be exported:

1.   From Network View 
   If the device is connected and online, right-click the device and choose "Export Device Design to File". This will pull the design from the hardware and save the file as an .sxml.
    
2. From Project View 
   Right-click the device block and choose "Export Device Design to File".
    

.sxml files can be imported to a specific device through the Project View:
Right click the device > "Import Device Design from File". After importing, double-click the device to view the schematic design.