
If you select "HD" then it produces a larger file that is great for viewing on a Mac. If you select "Medium" size, then it will produce a smaller file that uploads to the web more quickly. You will be prompted to tap the size you want to export. Tap "Share" button and then tap "Save Video" button. To save iMovie videos to the photo library, open "iMovie" on your iPhone and tap video clip which you want to save from the "Projects" browser or "Theater".

If you have an iCloud account set up, then you can also save your videos to iCloud Drive and then download then to your computer.

If you want to send you videos to your computer, then save them to the photo library from 'iMovie Theater' and then import them to your computer using iPhoto or Photos app.
