Google Docs has three different modes - editing, suggesting and viewing. By default, a document shared with other editors opens in editing mode. A document shared with viewers opens in viewing mode.
You can switch between the different modes by clicking the button in the top-right corner of the screen.
Note: Switching modes only applies to your view of the document. If you want everyone in the document to switch modes, you need to ask them to do it individually.
Using suggesting mode
1. Click the Editing button in the top-right corner of the screen.
2. Select Suggesting.
3. Add, edit or remove text in the document. Notice how your changes are presented as suggestions.
4. If required, add a comment to the Reply box to provide explanation for your changes.
Other authors can now review and approve/reject your suggestions. You can also approve, reject or delete your own suggestions. All suggestions are recorded in the Comments stream in Docs.
Tip: If you want all document editors to use suggesting mode, don’t forgot to ask them to switch modes before they start editing.