Microsoft 365 Copilot
Also known as: Copilot for Microsoft 365, M365 Copilot
Microsoft 365 Copilot is an AI assistant built into Microsoft 365 apps such as Word, Excel, PowerPoint, Outlook, and Teams.
It can draft documents, summarize email threads and meetings, analyze spreadsheets, and answer questions using the files, emails, and chats a user already has permission to see. It's sold as a paid add-on licence. While Copilot can save time, it can also surface overshared files that people didn't realize they could access, so permissions need cleaning up before rollout.
Microsoft 365 Copilot, explained at three levels
At home
Microsoft 365 Copilot is like an assistant who sits beside you and can read everything you're allowed to see at work: your email, files, chats and meeting notes. You ask a question or request a draft, the assistant looks up the relevant material, and then writes a first version for you. It works fast, but like any new assistant, its work needs checking.
At work
Microsoft 365 Copilot is a paid AI add-on built into Word, Excel, Outlook, Teams and other Microsoft 365 apps. It searches the emails, files and chats a user already has access to, then drafts, summarizes or answers questions from that material. Businesses care because it can save time on writing and meeting follow-up, but it also exposes any files that were shared too widely.
At home
Microsoft 365 Copilot pairs a large language model with your organization's own content. When you ask a question, Copilot first searches your emails, files, chats and meetings through Microsoft Graph, finding material you already have permission to see. It adds the most relevant pieces to your request, a technique called grounding, then the model writes an answer based on them. That is why it can summarize a meeting you missed, though it can still misread details.
At work
Copilot respects existing permissions: it shows a user only content they could already open. That also means it surfaces oversharing instantly, such as a salary spreadsheet in a SharePoint site open to everyone, which nobody had previously stumbled across. Prompts and responses stay within the Microsoft 365 service boundary and are not used to train the foundation models. Copilot is a paid add-on licence, while Copilot Chat offers more limited web-grounded features to Microsoft 365 users.
At home
Large language models predict likely text, which makes their writing fluent even when the facts are wrong. Copilot might misattribute a comment in a meeting summary, pull an outdated figure from an old file, or confidently fill a gap with something plausible. Its citations help you check. In my view, treat its output as a draft from a new employee: often useful, sometimes wrong, and always worth reviewing before you send it.
At work
Before rollout, audit SharePoint, OneDrive and Teams permissions, especially links shared with 'everyone' and broad site access, and use SharePoint Advanced Management or restricted search during cleanup. Apply sensitivity labels so Copilot respects encryption and usage rights. Pilot with roles that have clear use cases, measure time saved and quality, and train staff on prompting and verification. Review Copilot activity in Purview audit logs and set retention policies for its interactions.
Real-world examples
At home
Fatima missed a Teams meeting while sick. Copilot summarized the discussion and action items so she caught up in five minutes.
At work
Jerome's Regina MSP piloted Copilot for a client's sales team. A permissions review first found salary spreadsheets shared with everyone, which they locked down.
How it compares
| feature | Microsoft 365 Copilot | Copilot Chat (free) |
|---|---|---|
| Uses company data | Yes, files, email, chats | Mainly web and uploaded content |
| Works inside apps | Word, Excel, Outlook, Teams | Limited |
| Cost | Paid add-on | Included with business accounts |
| Permissions risk | Can surface overshared files | Lower |
Paid Copilot works with your company data. Free Copilot Chat mostly doesn't.
For analysts
For a Copilot business case, I'd pick a few measurable tasks, such as meeting summaries, and track time saved in a pilot before buying licences for everyone.
History & origin
Microsoft announced Microsoft 365 Copilot in March 2023, built on OpenAI's GPT models and Microsoft's own data connections. It became available to large enterprises in November 2023 at $30 US per user per month with a 300-seat minimum. In January 2024, Microsoft dropped the minimum, opening it to small businesses. In 2025, Microsoft made a free 'Copilot Chat' experience available to business users and added AI agents, and it later introduced lower-priced options for smaller organizations. Early adopters reported mixed results, with strong value in meeting summaries and email, and less in complex work. In my view, Copilot rewards organizations that have already organized their data.