With Office and OneDrive or SharePoint, multiple people can work together on a Word document, Excel spreadsheet, or PowerPoint presentation. When everyone is working at the same time, that's called co-authoring.
What do I need to co-author a document?
Co-authoring is available for documents stored in OneDrive or SharePoint.
To co-author with others, you need:
A shared storage area OneDrive, OneDrive for Business, SharePoint Online and SharePoint Server are shared storage areas which enable co-authoring.
Apps that support co-authoring Word and PowerPoint on all devices and versions more recent than Office 2010 support co-authoring. The Excel mobile apps and Excel 2016 with Office 365 also support co-authoring.
A co-authoring friendly document Co-authoring is only supported on modern file formats including: .docx (Word), .pptx (PowerPoint), and .xlsx (Excel).
Edit permissions for co-authors All co-authors must have permission to access and edit the documents.
Create or open documents for co-authoring
You can create documents in Office Online or Office desktop products. These topics will help you learn how to co-author documents:
Share your documents to collaborate and co-author with others
A key to collaborating and co-authoring is sharing your documents. In SharePoint, OneDrive, and Office apps you can share files with others.
To find out more about sharing documents in OneDrive and SharePoint, look at these topics:
When you open a shared document in a desktop or mobile app, it doesn't matter if you're connected or not, you can keep working. If there are others editing the same document, they won't be able to see your changes while you're offline. When you go back online, you'll be notified of any changes that are available, and others will see that you have changes.
When you're working in Word, the paragraph you're working in is locked so that no one can overwrite what you're working on. When you go offline with Word, it is possible to work on the same paragraph as someone else in your group. When you save your changes, you'll get a pop-up message saying there is a conflict. You can then click through to where you'll be able to sort it all out.
If you're working on a file that's in a sync folder (such as OneDrive or OneDrive for Business), it syncs when you come back online, regardless of whether the app (Word, PowerPoint) is running. When you reconnect, your file automatically syncs. If there are conflicts, you'll get an alert. For more info see Sync OneDrive.
By default, in SharePoint the groups and permissions assigned to a library where you store or create a document are inherited by all documents in the library. For example, on a team site where everyone has read/write permissions, anyone can co-author. While a SharePoint Online document library with read-only permissions only allows peopleto view documents, though no one but the author can make changes unless explicitly invited.
SharePoint permissions are inherited, but you can set different ones for specific people. If a SharePoint library shares for view only, you can give edit permission to some users. However, if the library is set for edit permissions for everyone, you can't restrict a few to just viewing. You can override inherited permissions with a higher permission, not a lower permission. For more info on permissions, see Understanding permission levels in SharePoint
With SharePoint MySite, OneDrive for Business personal library, or consumer OneDrive, your files need to be explicitly shared. By default, they can only be edited and viewed by the owner of the library. You can select who can edit individual files by sharing to people or groups with edit permissions. For more on sharing, see Share files or folders in Office 365.
Although you can upload files via Word and PowerPoint 2007 or earlier to SharePoint Online or OneDrive, and you can open them for editing, you can't co-author these documents with those legacy applications. When a user opens a document with Word or PowerPoint 2007, SharePoint Online or OneDrive creates a lock on the document and prevents other users of Office from editing that document. To take best advantage of co-authoring in Word or PowerPoint, it is recommended that all users work with at least Office 2010 on the desktop, Office Online, newer Mac or a mobile app.
Yes, Microsoft has worked with dozens of partners worldwide so you can co-author with Office Online. Check your storage provide to see if co-authoring with Office Online is supported.
There is no support, however, for third-party providers with Office desktop or other platforms and Microsoft does not support co-authoring documents stored on Google Drive.
Here are some links to get you started.
If co-authoring isn't working correctly, there are several things that can cause problems. To help troubleshoot your co-authoring sessions and setup, see Troubleshoot co-authoring in Office.
If you've shared your documents using OneDrive or OneDrive for Business you can receive an email message letting you know that the document has been updated.
Other topics of interest
If you haven't used Word Online or Office Online, you can test drive it here: Word Online. To change to a different online app, click the app launcher and choose another app.
For SharePoint administrators:
Note: For more information about how to co-author documents, search the Help for Word, PowerPoint, and Office Online. For more information about configuring SharePoint for document collaboration and co-authoring, see the TechNet web site.
Note: Co-authoring is not available for documents protected with Information Rights (IRM) or Rights Management Service (RMS).
Updated October 2017 thanks to customer feedback.