I can't export imovie videos from my mac to iphone?

I made a video on iMovie on my Macbook, and I saved it to the theatre. I then saved it as a file onto my Mac and it worked perfectly good. I tried to airdrop it to my iphone, and it airdropped but the video I received was plain white and wouldn't play. I sent it to my ipad and other devices but nothing worked. Then i saved the movie as a file again onto my usb. It worked on the usb great when it was plugged into my mac, but on my samsung laptop, it would show a black screen and only play the audio! Is it the format? Did I download it wrong? I really need to get it onto a usb or my phone as soon as possible because it is a school project!

Ok so to me it sounds like the video file is not compatible on your phone, you did not download it wrong however you just have to convert it to a video file so that it is compatible on iphones, here are a few that work for 5S and up.m4v, .mp4, and.mov.

I'm not sure what type phone you have so I'm not sure what files will work, however the ones above should work fine.

For iMovie 2013 or later, go back to iMovie, and open the original project (not that finished file). Then read the instructions in the link in "Source" below about Exporting as a Quicktime file. The format should be MPEG-4 (MP4) to be universal (Android, iOS, OS X 10.6 or later, Windows 7 or later).

For iMovie '11…
- Go back to iMovie, and open the original project (not that finished file).
- Share > Export using QuickTime.
- For the "Export" drop list, choose "Movie to MPEG-4".
- Click "Options" button.
- Set the Video Format" to "H.264".
- Data Rate determines the quality and file size, so try 2000.
- To minimize the file size for tiny iOS screens, "Optimized for: Downloading".
- Image size can be 1280 x 720 HD, unless you need a very small size.
- Frame Rate should match that of the original project, such as 29.97.