Co-authoring documents in Microsoft 365 lets your whole team edit the same Word, Excel, or PowerPoint file at the same time, in real time, without emailing attachments or merging conflicting versions. Save the file to OneDrive or SharePoint, share it, and everyone works on the same live copy simultaneously.

The Old Way Was Costing You Time

You know the drill. Someone emails a document to three colleagues for review. Each person opens their own copy, makes changes, and replies with their version attached. By Friday afternoon, the inbox contains four different files, all named something like “Proposal_v2_JSmith_FINAL_edited.docx”. Someone has to manually merge every change, and inevitably something gets missed.

This workflow is slow, error-prone, and completely unnecessary if you are using Microsoft 365. Co-authoring exists specifically to eliminate this problem.

How Co-Authoring Works in Microsoft 365

Microsoft 365 supports real-time co-authoring in Word, Excel, and PowerPoint. When a document is stored in OneDrive or SharePoint, multiple people can open and edit it simultaneously. Changes appear for all editors within seconds, not on a manual refresh.

Each person’s cursor and edits appear in a distinct colour, so you can always see who is working where. The experience works in the browser (Office Online), in the desktop apps, and on mobile. Everyone is always looking at the same document, and the same version.

How to Set Up a Document for Co-Authoring

The document must live in OneDrive or SharePoint before co-authoring can begin. A file sitting on someone’s local hard drive cannot be co-authored.

1. Save or move the document to OneDrive or a SharePoint document library.
2. Open the file and click Share in the top right corner.
3. Enter the names or email addresses of the people who need access.
4. Choose their permission level, either “Can edit” or “Can view”.
5. Click Send, or copy the link and share it directly.

That is the full setup. Anyone who receives the link and has edit permission can open the document and start working immediately alongside you.

Seeing Who Else Is Editing

Presence indicators make collaboration transparent. When a colleague is actively working in the document, their name or initials appear near the top of the screen. In Word and PowerPoint, you can also see a coloured flag showing exactly where their cursor is positioned in the document right now.

This means you can coordinate in real time. If two people are working on the same section, you will see that immediately and can divide the work without stepping on each other.

Version History: Your Undo Button for the Whole Document

Co-authoring does not mean you lose control of the document. Microsoft 365 automatically saves a version history as people work. You can view and restore any previous version at any time.

To access version history in Word or Excel, go to File > Info > Version History. In SharePoint, right-click the file and select Version History. Each saved version shows the date, time, and who made changes. Click any version to preview it, and choose Restore if you need to roll back.

This gives every team member a safety net. If a change goes wrong or content is accidentally deleted, recovery takes seconds.

Comments and @Mentions for Cleaner Feedback

Rather than inserting feedback directly into the document text, use comments to keep suggestions separate from the content. Highlight the relevant text, right-click, and select New Comment.

Use @mentions to direct feedback to a specific person. Type @ followed by their name inside a comment, and they will receive an email notification with a direct link to that section of the document. This removes the need for separate follow-up emails and keeps all feedback anchored to the relevant content.

When feedback has been actioned, mark the comment as resolved. Resolved comments are hidden by default but remain accessible in the comment history if you need to refer back.

Track Changes Alongside Co-Authoring

Track Changes works alongside co-authoring and is particularly useful when a document goes through review or approval stages. With Track Changes enabled, every edit is recorded with the author’s name and a timestamp, and the original text is preserved until a change is accepted or rejected.

To turn it on in Word, go to Review > Track Changes. Each co-author’s tracked changes appear in their assigned colour, so you can see exactly who suggested what. An editor or document owner can then review all proposed changes and accept or reject them individually or all at once.

Common Issue: The Exclusive Lock

Co-authoring can be blocked when someone opens a document using an older desktop application that does not support real-time collaboration, or when they open it from a local copy rather than the shared cloud location. In this situation, Microsoft 365 places an exclusive lock on the file, and other users cannot edit it while that session is active.

If this happens, check with your team to see who has the file open. Ask them to close the locally stored version and reopen it directly from OneDrive or SharePoint in a supported application. Office 365 apps from 2016 onwards generally support co-authoring, but older versions may not.

How Microsoft Copilot Helps in Co-Authored Documents

If your Microsoft 365 plan includes Copilot, it becomes genuinely useful in documents with multiple contributors. Copilot can summarise all comments and suggested changes in a document, giving you a clear overview of outstanding feedback without reading every thread individually.

When two authors have made different edits to the same section, Copilot can help reconcile the differences by drafting a consolidated version that incorporates both sets of changes. You still make the final call, but Copilot does the heavy lifting of comparison and synthesis. This is especially useful in longer documents where tracking all contributions manually takes significant time.

Moving Away from the Email-Attachment Loop

The shift to co-authoring is not just a technical change. It changes how your team collaborates. Feedback becomes faster and more specific. Version confusion disappears. The document owner always has a clear picture of who has contributed and what remains to be resolved.

If your team is still emailing documents back and forth, the first step is simply moving those files to SharePoint or OneDrive and sharing the link instead of the attachment. From there, co-authoring kicks in automatically.

If you need help setting up SharePoint libraries, configuring sharing permissions, or rolling this out across your team, get in touch with the Otto IT team. We can get your document workflows running the way they should.

Ready to stop the version chaos? Book a quick call with our team and we will help you get co-authoring working across your organisation.

Frequently Asked Questions

Does co-authoring work on Mac and mobile?

Yes. Co-authoring works in the Microsoft 365 apps on Mac, iOS, and Android, as well as in any modern web browser. The experience is consistent across devices, and all edits appear in real time regardless of which platform each person is using.

Can we co-author a document with someone outside our organisation?

Yes, as long as your SharePoint or OneDrive sharing settings allow external access. You can share a link with anyone, and they can co-edit the document using a Microsoft account or a one-time access code, depending on how your administrator has configured external sharing.

What happens if two people edit the same sentence at exactly the same time?

Microsoft 365 handles simultaneous edits using conflict resolution logic built into the sync engine. In most cases, changes merge automatically without either person losing their work. In rare cases where a conflict cannot be resolved automatically, you will be prompted to choose which version to keep.

Will co-authoring work if someone is offline?

The Office desktop apps support limited offline editing. Changes made offline are synced back to the shared document when the connection is restored. If another person edited the same section while you were offline, the sync process will attempt to merge the changes and flag any conflicts for review.

Do we need a specific Microsoft 365 plan to use co-authoring?

Co-authoring is available on all Microsoft 365 business and enterprise plans that include OneDrive and SharePoint. It is not available with standalone Office licences that do not include cloud storage. If you are unsure which plan your organisation is on, contact Otto IT and we can check for you.