Quick Fill is the fastest way to fill a whole month at once on iOS. It looks at the date each photo or video in your library was taken and lines it up with the matching day in your project, one month at a time. You review every snippet before it's added, and snippets you've already created aren't replaced.
Quick Fill is available on iOS. On Android, use Auto-Fill. To fill a single day from its context menu, use Autofill instead.
Steps
Open a project and scroll the calendar to a month with days showing a video camera icon.
Tap "Quick Fill" at the top-right corner of the calendar.
Select the month or months you want Quick Fill to fill.
Tap "Show Preview" to see the snippet chosen for each day.
If you'd like a different one, tap "Edit" and scroll to that day: Swap picks another video from the same day, Remove takes the day out of the selection, and Adjust lets you trim the snippet.
When you're happy with the selection, tap the teal checkmark, then tap "Add to Project".
That's it! The snippets Quick Fill chose now appear on their days in the calendar. Days without a video camera icon have no photos or videos in your library from that date, so Quick Fill leaves them empty—tap one of those days to add a snippet by hand.
