Co-authoring enables you and your colleagues to work on the same Excel workbook simultaneously. Everyone sees all changes in real-time, and across all devices that run Excel for Office 365, for the web, or any mobile version.
To co-author in Excel, you need the latest version of Office 365.
Share Your Workbook for Co-Authoring
To co-author a workbook, you first need to save it to OneDrive or a SharePoint Online library. To share your workbook with others, click “Share” in the top right corner.
If you haven’t already saved the workbook you want to share to OneDrive or SharePoint, you’ll be prompted to do so.
When the Share pane opens, type the email addresses of the people with whom you want to share the workbook.
Next, click the drop-down button to decide whether each person can edit or just view the workbook. You can also type a message if you’d like.
Click “Share” to send an email to everyone you invited.
The people you invite can click “Open” in the email invitation to open the shared workbook.
If you don’t want to share the workbook via email, click “Get a Sharing Link” at the bottom of the Share pane, and you share it any way you’d like.
You can see a list of everyone with whom a workbook was shared in the Share pane.
How Others Can Open a Shared Workbook
The first time someone opens a shared workbook, it opens in Excel on the web. The person can edit the file in Excel online, as well as see who else is in the workbook and what changes they make.
If someone wants to work in the desktop version of Excel, he can click “Open in Desktop App.”
Co-Authoring in Excel
In most versions of Excel—including Office 365, for the Web, and for mobile—you see your co-authors’ selections in real-time. And each person’s selections appear in a different color so you can identify them easily.
Unfortunately, not all versions of Excel support this feature. Even if you can’t see their selections, though, you’ll see the changes other authors make.
To see the selections of all co-authors in real-time, you have to use Excel for Office 365 and turn on the AutoSave feature—you’ll find it in the top-left corner of the toolbar.
Annotate with Comments
A great way to collaborate without changing cell values is to use comments. Comments makes it easy to leave a note or have a conversation in Excel before you make a change.
To add a comment, click the cell you want to comment on, and then click Review > New Comment.
Type your comment, and then click the Post button (the green arrow icon).
The comment appears with an icon in the corner of the cell the same color as your co-authoring ID.
All authors can read your comment when they position their mouse over the cell.
To reply to a comment, click the comment icon. The Comments pane opens, and you can type your reply.
If you want to see all the comments in a workbook, click “Comments” in the top-right corner.
The “Comments” panel opens, and you see all the comments in the workbook in a conversational format. Each comment also includes a reference to the cell in which it’s stored.
The option to have conversations in the workbook via Comments is a great advantage over using an external method, like email or Skype.