Mariano shows How to add a “Cover Letter” page to a Microsoft Dynamics GP Word Template document over at the Dynamics GP Blogster.
The Dynamics GP Blogster: How to add a “Cover Letter” page to a Microsoft Dynamics GP Word Template document
Excel & OfficeTips & Hidden FeaturesMicrosoft & the GP Ecosystem
Archived post from 2012. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.