To access the Restrict Editing panel and enforce protection, click 'Restrict Editing' in the 'Protect Document' drop-down button of the File menu, or click 'Restrict Editing' in the Protect group of the Developer ribbon.
Right-click on one of the tabs and then click 'Customize the Ribbon…' Check the box next to 'Developer' under Main Tabs and then click the 'OK' button to enable the Developer ribbon. You can also enable the Developer ribbon to access additional document protection commands. Click the 'Protect Document' drop-down button and then select one of the available options. You can access the document protection options in Word via the Info pane of the File menu. Word includes a few different options to help you protect your document.