From the GP team, news you can use. Document Attach vs. Notes and how to locate whether a master record has a document attached.
Document Attach vs. Notes and how to locate whether a master record has a document attached. – Microsoft Dynamics GP Community
Tips & Hidden FeaturesMicrosoft & the GP Ecosystem
Archived post from 2016. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.