Andy Sather explains Printing Subtotals in the Footer of the last page using Microsoft Dynamics GP Word Templates.
Printing Subtotals in the Footer of the last page using Microsoft Dynamics GP Word Templates – Dynamics GP Support and Services Blog
Excel & OfficeMicrosoft & the GP Ecosystem
Archived post from 2011. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.