Information
This policy setting controls whether Outlook displays the 'Add Signature Services' menu item.
The recommended state for this setting is: Enabled
By default, users can select Add Signature Services (from the Signature Line drop-down menu on the Insert tab of the Ribbon in Excel, PowerPoint, and Word) to see a list of signature service providers on the Microsoft Office Web site. If the organization has policies that govern the use of external resources such as signature providers or Office Marketplace, allowing users to access the Add Signature Services menu item might enable them to violate those policies.
Solution
To establish the recommended state via configuration profiles, set the following Settings Catalog path to Enabled :
Microsoft Office 2016\Signing\Suppress external signature services menu item
Impact:
Enabling this setting prevents users from adding a signature service from Microsoft Office.com but should not otherwise cause significant usability issues for most users.