CodeTwo Signatures Add-in for Outlook

You can set up organization-wide signatures that will be automatically inserted into an email (a new message and reply/forward) directly in Outlook as users type. Users can also manually select a different client-side signature in Outlook. There are two CodeTwo add-ins that can help with that: 

  • New experience: CodeTwo Signatures Web Add-in for Outlook that works with Outlook for Windows and Outlook on the web (OWA). This modern Web Add-in comes with new capabilities and offers better experience. It is also available on Microsoft AppSource.
  • Classic experience: CodeTwo Signatures Add-in for Outlook (COM Add-in) that works with Outlook for Windows only.

Both add-ins work only with client-side signatures, so make sure that CodeTwo Email Signatures for Office 365 operates either in client-side or combo mode in your organization (learn more about signature modes). You also need to create and configure at least one client-side signature rule (see our guide on that). 

See the table below for a quick comparison of the two signature add-ins for Outlook available for CodeTwo Email Signatures for Office 365:

  Modern Web Add-in Classic COM Add-in
Supported platforms

Outlook for Windows

Outlook on the web (OWA)
Outlook for Windows
Deployment Central via the Microsoft 365 admin center
(for all or selected users)

Deployment instructions
Central via GPO or individual by Outlook users

Deployment instructions
How are signatures inserted? Automatically (event-based) or manually (via the CodeTwo Signatures pane) Automatically or manually (via the Outlook's Signatures command) 
Who gets signatures? Users defined in client-side signature rules Users defined in client-side signature rules as well as other Outlook users1
User log in requirement No Yes
How often the add-in syncs with CodeTwo services? Real-time synchronization2 Every couple of minutes or manual

1 Client-side signatures added by the COM Add-in can be accessed by and used with other accounts configured in the same Outlook app where the add-in is installed.

Changes made in the signature management app are instantly applied to signatures in Outlook.

Follow the links below to learn more about:

You can only use either of the add-ins, so deploy the one that best matches your preferences. If you have already deployed one of them, uninstall it first before deploying the other one. Otherwise, the add-ins can conflict with each other.

Modern CodeTwo Signatures Web Add-in for Outlook

The modern CodeTwo Signatures Web Add-in for Outlook, co-engineered with Microsoft, adds signatures to emails in Outlook for Windows and Outlook on the web / OWA (soon also in Outlook for Mac). 

Web Add-in deployment

The add-in needs to be centrally deployed by a global admin from the Microsoft 365 admin center (or Microsoft AppSource) to all or selected users. There’s nothing to install on local machines. See this article for the Web Add-in deployment guidelines

How to use the Web Add-in

Once you start typing an email in Outlook, a signature is automatically inserted into the email body, according to the configured client-side rules (Fig. 1.). For example, a different signature is inserted to new messages and a different one to replies/forwards. The Web Add-in uses the newest event-based activation feature from Microsoft, which means every time you make changes to a message (e.g. select a different sender in Outlook), the Web Add-in changes the signature as well, in real time.

The signatures Web Add-in for Outlook automatically adds a client-side signature to the body of an email.
Fig. 1. The signatures Web Add-in for Outlook automatically adds a client-side signature to the body of an email.

If the event-based activation doesn't work in Outlook for Windows, it may be that your version of Outlook doesn't fully support the Web Add-in. Try updating your Outlook or change the Microsoft Apps update channel, as described in this article by Microsoft. You can still add signatures manually, as described below.

Learn more about the supported version of Outlook 

To insert a signature manually, first either click the Open add-in pane link at the top of an email you are composing or the CodeTwo Signatures button on the ribbon (Fig. 2., items 1). Next, in the pane that opens, click Use this signature below the signature that you want to use (Fig. 2., item 2).

Inserting an email signature manually from the CodeTwo Signatures pane.
Fig. 2. Inserting an email signature manually from the CodeTwo Signatures pane.

To open the CodeTwo Signatures pane while composing a message in Outlook on the web (OWA), either click the Open add-in pane link at the top of the message (Fig. 3., item A) or click the ellipsis button (...) at the bottom of the message and then select CodeTwo Signatures (Fig. 3., item B).

Opening the CodeTwo Signatures pane in Outlook on the web / OWA.
Fig. 3. Opening the CodeTwo Signatures pane in Outlook on the web / OWA.

Using the Web Add-in in combo mode

Note that if CodeTwo Email Signatures for Office 365 works in combo mode, your server-side signatures can still be added to emails sent from Outlook clients. However, this will only happen if there are both server-side and client-side signature rules defined for your account and if no client-side signature is added by the Web Add-in in Outlook (either automatically or manually).

Classic CodeTwo Signatures Add-in for Outlook (COM Add-in)

CodeTwo Signatures Add-in for Outlook adds client-side signatures to emails in Outlook for Windows.

COM Add-in installation and configuration

The add in can be installed centrally by the admin (see instructions) or manually by individual users (as described here).

How to use the COM Add-in

To have access to client-side signatures, you need to log in to the add-in with your Microsoft 365 account credentials. CodeTwo signatures added by the COM Add-in are available just like any other Outlook signatures. If they are set as default by your organization's admin, they are added automatically when you compose a new message or when you forward/reply to an email (Fig. 4.). 

CodeTwo Signatures Add-in for Outlook automatically adds your default signature as you type. You can also preview the other available signatures via the add-in pane.
Fig. 4. CodeTwo Signatures Add-in for Outlook automatically adds your default signature as you type. You can also preview the other available signatures via the add-in pane.

You can also add them from your Outlook ribbon - in compose mode, go to the Message tab, click Signature on the ribbon (Fig. 5.) and choose any signature that is available to you (if a signature is already added to your message, it will be replaced with the one you selected).

ESIG 365 Signatures Add-in for Outlook ribbon v3
Fig. 5. You can use Outlook's ribbon to add/change a signature.

Click the add-in button on the Outlook ribbon to show/hide the add-in pane. Note that the button might not be visible if you open a message in a new window. You can use the add-in pane to:

  • quickly preview the signatures that are available to you,
  • force signature refresh (Fig. 6.) if you do not want to wait for automatic signature synchronization that occurs every couple of minutes,
  • sign in or sign out of your user account.

You can access the Force signature refresh functionality by opening the add-in pane.
Fig. 6. You can access the Force signature refresh functionality by opening the add-in pane.

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