This is not a permanent addition to Word. Once downloaded the add-on. unzip the file and get .dot template file. To use it temporarily Double-click the template, it will be open Word with the Add-in enabled. The add-in will disappear once it is closed
To use it template permanently, open Word's Templates(normal.dot) and click on Add-ins dialog box, click the Add button, and select the Clean Up Text.dot file.
[To open Templates and Add-ins in Word 2003, click Tools -> Templates and Add-ins. In Word 2007 and 2010, click the Add-ins button on the Developer tab. If the Developer tab isn't visible in Word 2007, click the Office button -> Word Options -> Popular and check Show Developer tab in the Ribbon. In Word 2010, make the Developer tab appear by clicking File -> Options -> Customize Ribbon and check Developer in the right pane.)


To download click here Clean Up Text