How do i export a movie to play on iphone

Export (share) the movie to your desktop and then use the AirDrop feature on your Mac and iPhone to transfer the video to your iPhone. AirDrop must be enabled on both devices and the devices must be located no more than 30 feet apart.

-- Rich

If the video is a short one you can email it to yourself and transfer it to your iPhone that way. Larger videos, up to 5GB, can be emailed with a free iCloud mail account that you can set up on your Mac. (AirDrop, on the other hand, doesn't have a file size limitation, which is nice.)

You can also use iCloud to share photos and videos between devices. See the Finder help menu and type in "iCloud sharing".

-- Rich