How to Allow Multiple Users to Edit a Word Document at the Same Time

Track Changes
1. Click the 'Review' tab on the top toolbar.
2. Click 'Final Showing Markup' so that the document shows your edits.
3. Click 'Track Changes' in the Tracking section.
4. Make changes, including deletions and insertions, in the document.
5. Click 'Balloons' in the Tracking section and choose 'Show Revisions in Balloons' if you want changes to be shown in balloons on the right side of the text. Alternatively, choose 'Show All Revisions Inline' from the 'Balloons' button if you want changes to be shown in the regular text.
Combine Documents
6. Click the 'Review' tab on the top toolbar.
7. Click 'Compare' and then 'Combine.'
8. Click the 'Folder' icon under 'Original Document' and locate your original document.
9. Click the 'Folder' icon under 'Revised Document' and locate the revised document sent by an editor.
10. Select 'New Document' under the 'Show Changes In' section.
11. Click 'OK.'
12. Accept or reject the editor's changes and save the document under a new name.
13. Repeat Steps 1 through 7 to combine changes in another editor's document into the revised document.