The Signature 365 add-in for Outlook allows users to preview signatures, add signatures to emails so they appear directly below the email being composed, and select an alternative signature if additional signatures have been assigned to them.
Information
The Outlook Add-in is only supported for Outlook 365 subscription versions due to limitations from Microsoft.
If you are using perpetually licenced versions of Outlook (2016 / 2019 / 2021) you will need to use the Outlook Agent following the instructions here: How to install the Outlook (Classic) agent
The add-in can be deployed from the Microsoft 365 Admin Center to apply to users, groups or your entire organisation, or it can be installed from the "Get Add-ins" option in Office 365 for individual users or testing purposes.
Warning
Outlook Add-in must be deployed to your users using one of the methods below. If the add-in is installed manually by a user from the Add-in store, it will be unable to insert signatures due to a security limitation imposed by Microsoft.
Log on to the Microsoft 365 Admin Center as a Global Administrator.
Go to Settings > Integrated apps to open the Integrated apps page, the Signature 365 application web app will show as More apps available.
Click on the application name, and the following fly-out will appear. Click the Deploy button to start deployment. This will initially only deploy to the user that completed integration with Signature 365.
You will see the following screen whilst the admin center deploys the app.
When this step completes, the following screen will appear. The app has been added to your Microsoft 365 tenant and now must be deployed to your users. Click Done to finish this step.
Select the Users tab, and select the users you wish to deploy the add-in to, then click the Deploy button.
You can change this option later and/or edit any specific users/groups you initially choose. Note that when selecting the Specific users/groups option, this will by default send the users an email notification unless you disable this option.
Whilst it is possible to deploy to the entire organisation, we recommend creating a dynamic security group of users within Microsoft Entra, due to Microsoft not providing an option to exclude users from a deployment.
Important
Please note, when using Specific users/groups option, Microsoft 365 will only deploy the add-in to users that are direct members of any groups you specify. Members of any nested groups will not be included. This is a limitation of Microsoft 365.
The following screen will be displayed, when both apps show as Completed, click Done.
Important
The add-in may not be available to all users immediately. The deployment usually only takes a few minutes but can take up to 6 hours according to Microsoft. For some users the add-in may not be available until Outlook has been restarted.
Click Done to close the add-in pane.
The Outlook add-in is now visible in the Microsoft 365 Admin Center and will deploy to your selected users.
Information
Microsoft are in the process of removing the Get Add-ins option from Classic Outlook. You will need to use this option if you see All Apps as a menu item.
Open a browser and navigate to https://outlook.signature365.com/manifest.xml
Use your browser to save the webpage to your machine - in the Chrome or Edge menu -> More Tools -> Save page as...
Select File from the menu within Outlook, and select the Manage Add-ins item.
This will open OWA in your default web browser. In the Add-ins for Outlook window that opens, select My add-ins, and scroll down until you see the Custom Addins section.
Click + Add a custom add-in and in the dropdown that appears select the Add from File... option. Please note the Add from URL... option has been removed by Microsoft.
In the window that opens, select the manifest.xml file you previously saved.
Review the warning and select Install.
The Signature 365 add-in will appear in the Custom Addins section, and will now be available when composing a new message.
Open a browser and navigate to https://outlook.signature365.com/manifest.xml
Use your browser to save the webpage to your machine - in the Chrome or Edge menu -> More Tools -> Save page as...
In the Outlook menu ribbon, click the Get Add-ins button.
In some cases, the Get Add-ins button may be unavailable. If you see this issue, navigate to aka.ms/olksideload
In the Add-ins window that opens, select My add-ins, and scroll down until you see the Custom Addins section.
Click + Add a custom add-in and in the dropdown that appears select the Add from File... option. Please note the Add from URL... option has been removed by Microsoft.
In the window that opens, select the manifest.xml file you previously saved.
Review the warning and select Install.
The Signature 365 add-in will appear in the Custom Addins section, and will now be available when composing a new message.