What Highlights are
Highlights are short summaries of important things that don't need a reply, like a decision, an approval, or a booking. They're a paid feature on the Plus plan and up, so the free plan doesn't get them. Your secretary writes them as it processes your mail and sorts them by type.
What a Highlight is
A Highlight is something worth knowing that doesn't ask anything of you. A deal got approved, a meeting moved, a flight was booked, a project hit a milestone. There's no task to do and no reply expected, but you'd still want to know it happened.
Each Highlight is a short summary your secretary writes as it processes a message, so you can catch the point in a sentence or two without opening the thread. Highlights sit between Action Items, which need something from you, and FYIs, which you can mostly ignore.
Highlights are a paid feature
Highlights are part of the paid plans. They're included on Plus, Pro, and Ultra, and they're not part of the free plan. If you're on the free plan, your mail still gets read and sorted into Action Items and FYIs, you just won't see Highlights until you upgrade.
You can compare what each plan includes on the pricing page.
The types of Highlight
Your secretary sorts Highlights into a set of built-in types so similar things group together. You'll see types like these:
If a Highlight ever lands under the wrong type, you can fix it the same way you fix any sorted item. See Why an email landed in the wrong category.