export to iCloud drive via UIActivityViewController
<p>In iMovie for iOS, I can export a movie via <code>UIActivityViewController</code> to the iCloud drive (shown below). How can I implement this in my own app? Do I need to create a custom <code>UIActivity</code>? Currently "iCloud Drive" doesn't show up as one of the action categories.</p>

<p><a href="https://i.stack.imgur.com/PeIon.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PeIon.png" alt="iMovie share dialog"></a></p>