How to find an iMovie project file - Mac- iPad iMovie?
According to iMore : How to move an iMovie project from your iPhone or iPad to your Mac
you cannot transfer a project from Mac to iDevice, only from the iDevice to the Mac.


  Can I move projects back to my iPhone or iPad?
  
  Not at this time, sadly. You can keep working on the project file you exported—it opens in either iOS or OS X—but once you import it into iMovie on the Mac, you're stuck editing in the Mac environment.