Entries can be marked as Favorites to be searched or filtered to quickly identify special entries.
Swipe on any entry in the Timeline view and tap the More (•••) icon. Then tap Mark as Favorite. A heart icon will appear in the metadata line at the bottom of the entry.
You can also open the Entry Info/Metadata of an entry and favorite the entry.
Then you can use Filters to quickly sort and view all of your Favorites in the Timeline view.
There are 3 ways to mark an entry as a Favorite in Day One on Mac version 3 or later.
Click the More button (•••) at the top right of an entry, click Edit > Favorite.
Click the paper clip icon at the bottom right of an entry and choose Favorite.
Right-click (or Control+click) on an entry in the Timeline panel, click
Tap to open any entry. Tap the More (•••) icon at the top right and choose to Star the entry. This will also be changed to Favorite in the future.