Google Docs allows you to see who made which changes on any collaborative document, with as much or as little detail as you need.
To get started, click file, see revision history. A sidebar will open on the right side, detailing all of the recent document changes. Every person who edited the document appears in the sidebar, with a corresponding color.
Changes from different editors are highlighted in their assigned color. If you want to see additional detail, such as cell-by-cell revisions in a spreadsheet, click the Show more detailed revisions button at the bottom of the sidebar. To restore your document to a previous version, find the version you want in the history and then click Restore this revision under the editor's name. If you want to see document revisions without the color highlighting, uncheck the Show changes box at the bottom of the sidebar. To exit revision history without making any changes, click the X at the top of the sidebar.