Policy
Suppress external signature services menu item
This policy setting controls whether Outlook displays the "Add Signature Services" menu item. If you enable this policy setting, Outlook does not display the "Add Signature Services" menu item on the Signature Line drop-down menu. If you disable or do not configure this policy setting, 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 Office.com.
f862523e829a L_Supressexternalsigningservicesmenuitems Registry
Copy registry mappings
HKCU\software\policies\microsoft\office\16.0\common\signatures\suppressextsigningsvcs (enabled) = 1
HKCU\software\policies\microsoft\office\16.0\common\signatures\suppressextsigningsvcs (disabled) = 0Policy notes
This policy setting controls whether Outlook displays the "Add Signature Services" menu item. If you enable this policy setting, Outlook does not display the "Add Signature Services" menu item on the Signature Line drop-down menu. If you disable or do not configure this policy setting, 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 Office.com.