How to Use Copilot in Outlook: Summarize Threads and Draft Replies

The short version

Copilot in Outlook saves the most time on two jobs: catching up on long threads and getting a first draft of a reply. It works in new Outlook, classic Outlook, Outlook on the web, Outlook for Mac and the mobile apps, with slightly different buttons in each.

Step by step

Summarize a thread

1. Open the conversation.
2. Select Summary by Copilot (or Summarize) at the top of the thread. On iPhone and Android, tap the Copilot icon in the toolbar.
3. Read the summary at the top of the email. Numbered citations link to the message each point came from, so you can check it.
4. Summarize attachments in new Outlook and on the web with Summarize a file (PDF, Word and PowerPoint files).

Draft a new email or reply

1. Start a new email, reply or forward.
2. Select the Copilot icon in the toolbar and choose Draft or Draft with Copilot. In new Outlook you can also select Help me write or Help me reply in the message area.
3. Type what the email should say and select Generate.
4. Adjust tone and length (the dropdown in new Outlook, Adjust in classic Outlook, Options on mobile), or regenerate.
5. Keep the draft, edit it so it sounds like you, and send.

Prompts to copy

A reply that moves things forward:

Reply that I can do Thursday at 2 pm or Friday morning, ask which works,
and confirm I'll bring the signed quote. Friendly, under 80 words.

A polite no:

Decline this request for a discount politely. Explain our prices went up because of supplier costs
and offer free delivery on their next order instead.

A follow-up:

Write a short follow-up to my email from last week about the unpaid invoice #2041 for $1,250.
Firm but polite. Ask for payment or a date by Friday.

After a summary:

List the decisions made in this thread and anything still waiting on me.

Example

You have: a 23-message thread about moving an office event, with three people disagreeing.

You do: select Summary by Copilot, then reply with Draft with Copilot: “Confirm we’re going with the June 14 date and the downtown venue, thank everyone, and ask Maria to send the final headcount by Monday.”

A good result: a summary that names the date options and who preferred what, with citations, and a short reply you can send after changing one or two phrases.

Mistakes to avoid

• Replying from the summary alone. Click the citations for anything important; summaries can miss nuance.
• Leaving out the facts. Copilot can’t know your dates, prices or decisions unless you put them in the prompt.
• Sending the draft as-is. Check names, numbers and the tone.
• Using plain text. Draft with Copilot needs HTML messages in new Outlook and on the web.

Good to know

You can turn Copilot off in Outlook with the Turn on Copilot toggle: Settings > Copilot in new Outlook and on the web, Quick Settings > Copilot on Mac and mobile. See turn off Copilot.

Related: use Copilot in Teams meetings and write better Copilot prompts.