There are a number of different ways to export your finished movie.
For uploading to Youtube, Vimeo, Canvas, sharing with classmates, etc the best destination to use is Apple Devices 1080p.
The codec we recommend is H.264. It is very efficient and provides high-quality images and uses a lower bit rate resulting in a smaller file size that is much easier to be managed by streaming services who compress your file further.
If you export using ProRes settings, you can see how much bigger the file size becomes.
If your final product is a DVD, Thesis submission or perhaps an entry to a short film contest, you might want your share destination to be Master File instead of Apple Devices 1080p because that setting produces a type of Apple-specific .m4v extension which is optimized for playback within the Apple ecosystem – not necessarily outside it.
You can also share only a part of your video by using the range selector.