Journal
Tags and filters in the Journal
Tag entries with your own words, then show only entries with a tag, attachments or people.
The Journal has its own tags, by name, shared across all its entries. In an entry, tap Tags (beside Copy); its tags show as chips there.
With Auto-tags on, a new entry with no tags is tagged once you pause typing; each automatic tag shows a ✦ until you change it.
Filtering
The filter (in the bottom-left capsule) shows only entries with any of the tags you pick, entries with attachments, or entries with people. A line says what's filtered, with Clear.