Scenario
You want to prioritize signatures deployed by the Outlook Add-in by removing the built-in signatures options from Outlook on the Web (OWA).
Resolution
You can remove the built-in signatures options from OWA by disabling the feature in the OWA mailbox policy in Exchange Online.
WARNING! Disabling the signature options will stop users from creating or modifying signatures in OWA; however, existing signatures will not be removed. Microsoft does not currently provide any way for Admins to delete the users roaming signatures. Existing signatures will still show up in OWA when the feature is disabled.
Please click on the required options listed below to go through the detailed description:
Disable signatures in Outlook on the Web
To disable signatures in Outlook on the Web:
- Sign in to the Exchange Online admin portal as an Administrator. The Exchange admin center is displayed.
- From the menu sidebar, select Roles, then select Outlook web app policies.
Select Roles then select Outlook web app policies. - Select the OWA policy. The details of the selected policy are displayed.
Select the OWA policy. You can see the selected policy details on the right. - In the Features, select Manage Features.
- Expand the User experience drop-down and unselect Email signature.
Expand the User experience drop-down and unselect Email signature. - Select Save changes.
Disable signatures for all mailboxes' in Outlook on the Web
To disable signatures for all mailboxes' in Outlook on the Web:
- Open a PowerShell window and connect to Exchange Online.
- Run the following command to disable Outlook Web signatures from all mailboxes:
set-OwaMailboxPolicy * -SignaturesEnabled $false