If you install the free Collavate add-on for Google Docs or Google Sheets through its Add-on feature, you can use the Approval Process function while you use Google Docs.
Users may find this useful because this allows the approval process to be accessible directly from a google drive file screen.
After the installation, you can use the Collavate Google Docs Add-on by following steps.
1. Click the Add-ons on the top menu from Google Docs/Sheets UI.
2. Click Collavate.
3. Click Start, and start the Approval Process.
4. Add Reviewers to process
5. Click Submit for Approval