How to send models/drawings to service desk
If the matter concerns only a single part model, you can attach it as it is to the support request you create in the Service Desk.
If it is an assembly or any model that also has one or more drawings, it is always best to send the entire design in .vxz format.
From the File menu, select Export → Save as compressed file – choose which levels to export (select "Transfer the entire structure").
Save the file in .vxz format and attach it to your support request in the Service Desk.
If the model is too large to attach in this way, save it to an external file-sharing service (such as WeTransfer) and include the link in the support request.