iMovie problem

In the past, after I produced a project file in iMovie in my iMac. I could easily transfer it to iTheatre. The file then automatically uploaded to iCloud and I could downloaded it to google drive in my iPhone X, from which I could also copy the link to my friends.

But now the iTheatre in my iMac stops its function. May I know how could I upload the project file from iMovie to iCloud so that my friends can view the project through my iPhone X ?