1. Click on the 'File' tab in the Word ribbon.
2. Choose 'Options' in the 'File' menu to display the Word Options dialog box.
3. Click on 'Advanced' in the left column of the Word Options dialog box.
4. Click to remove the checkmark from the 'Use Overtype Mode' box. You can also choose to enable or disable the 'Insert' key's control of overtype mode while you're here.
5. Click the 'OK' button to return to your document.