I am a novice to many things but a complete novice to iMovies. Just had a VHS tape digitized and had Apple Help walk me through editing it (taking out clips) using iMovies. I used iMovies because that is what the Apple tech said to use. Got that done (finally) this afternoon; not the easiest thing to follow. Did see that it was saved as an MP4 file, of which I know absolutely nothing, and saw that it played on my MacBook Pro. Sent the file via email to my daughter who also has a MacBook Pro (albeit older than mine). Asked her if it worked, and she said "yes, after I remembered what my password was for Microsoft OneDrive". I am going "what"?!? What does iMovies and/or MP4 files have to do with Microsoft OneDrive? I didn't have to bring up OneDrive to play it. Need to know what to tell other people, Mac and Windows, what to do if I forward more copies.