You can search for keywords, phrases, locations, and tags in Day One. This can be limited to the current journal or all entries.
Tap the Search icon at the top of the Timeline view to begin a search.
Type the search criteria and entries will begin to appear. The search defaults to All Entries, but users can switch to specific journals once the word or phrase is searched.
Click the Search icon at the top or use Command-Shift-F to search all data in Day One.
Or within an entry use Command-F to search words in an entry.