Registration and configuration of a Microsoft 365 (Office 365) tenant

After you created a CodeTwo Admin Panel account and signed in, it's time to register your Microsoft 365 (Office 365) tenant to our service and specify how signatures should be added to this tenant. See step-by-step instructions below or check out our video tutorial:

You can add a new tenant to the Admin Panel directly from the Dashboard, by clicking the Add (ESIG for O365 add button 14px) button on the Tenants card (see Fig. 1.). Alternatively, go to the Tenants tab and use the Add new tenant (ESIG for O365 add tenant2 button 14px) button.

CodeTwo Admin Panel - Dashboard view.
Fig. 1. CodeTwo Admin Panel - Dashboard view.

In either case, a configuration wizard will open. Read on or use the links below to learn about all the steps.

In the first step (1. License agreement), read and accept the terms and conditions (Fig. 2.).

Registering a new tenant to CodeTwo Email Signatures 365, step 1.
Fig. 2. Registering a new tenant to CodeTwo Email Signatures 365, step 1.

In the next step (2. Sign in – not shown here), click Next and you will be redirected to the Microsoft account sign-in website (Fig. 3.). Sign in with your Microsoft 365 global admin credentials – this is the only account type that has all the permissions required by the program to add personalized email signatures.


The program uses Azure OAuth 2.0 authentication. Your credentials are safe, because they are passed directly and only to Microsoft servers; they are never stored on any CodeTwo or third-party servers.

The Microsoft 365 sign-in page.
Fig. 3. The Microsoft 365 sign-in page.

Accept the permissions necessary to run CodeTwo Email Signatures 365 with your tenant.

After that, in step 3. Region (Fig. 4.) you need to select a region for the CodeTwo Email Azure Service (which adds signatures and stores your settings). Choose the location of the server in which your Microsoft 365 tenant resides (or the nearest one) and click Next.


Be sure to choose the right location for CodeTwo services as it is not possible to change this later without deregistering your tenant (which will also cancel your subscription). If you need to modify your region, please contact our Support.

Choosing the location of the CodeTwo Email Azure Service.
Fig. 4. Choosing the location of the CodeTwo Email Azure Service.

Step 4., Signature mode (Fig. 5.), is where you decide how signatures should be added in your organization. You can choose the following signature modes:

  • Server-side mode: selected by default because it works with all email clients. In this mode, a signature is added after an email is sent. You can still preview the signature as you type an email by deploying a dedicated Web Add-in (centrally from the Microsoft 365 admin center).
  • Client-side mode: works with Outlook for Windows, Outlook for Mac and OWA. A signature is added automatically when you compose a message, or you can select a different signature manually in Outlook.
  • Combo mode: works with all email clients. It's a combination of the server-side and client-side modes. Signature is added as you type an email in Outlook. If you use other email clients, signature is added after an email is sent.

When you select a mode, the program shows how your mail flow will look like and provides a comparison table. You can also learn more about signature modes in this article. Read on or use the links above to learn about all installation scenarios.

Signature mode selection.
Fig. 5. Signature mode selection.

Server-side mode provisioning

To continue setting up your tenant in the default signature mode, leave Server-side mode selected, scroll down and click Register (see Fig. 5.). A successful tenant registration will be confirmed in the last step of the wizard (5. Provisioning), shown in Fig. 6.

Successful tenant registration in the server-side signature mode.
Fig. 6. Successful tenant registration in the server-side signature mode.

Directly after tenant registration, you need to wait (usually for about 3-15 minutes) for our services to be provisioned before you can proceed with further configuration.

What is server-side provisioning?

It's a process of assigning a unique certificate that's necessary for the correct operation of Exchange Online connectors (which will be configured later). This process does not occur in client-side mode.

You can track the provisioning status for your tenant on the Tenants tab, by refreshing the page. When the process is finished, the Signature mode status on your tenant's card will change from Provisioning in progress to Connectors configuration required (Fig. 7.). You will also get an email notification with further setup instructions.

The tenant card status displayed after the server-side provisioning is completed.
Fig. 7. The tenant card status displayed after the server-side provisioning is completed.


Once the provisioning of our services is finished, a new accepted domain will be added to your Microsoft 365 tenant: [your unique ID] You can find the domain by following these steps.

Do not remove this new domain - it's the new requirement from Microsoft, to make your email even more secure. If you remove it, the program will not work correctly. If you accidentally deleted the new CodeTwo domain from your Microsoft 365, follow the steps described in this article.

Please do not verify this domain in your Exchange admin center. If Microsoft 365 sends you notifications or warnings (e.g. to update the domain's DNS settings), you can ignore these warnings - your mail flow is not affected. Learn more

At this point, your tenant is almost ready - you only need to complete a few additional steps to finish the tenant's configuration. To learn more, click the Connectors configuration required status on your tenant's card (Fig. 7.). The program will show additional information and redirect you to the Next steps page (Fig. 8.), where you will learn what is required to finish the configuration of your tenant.

The Next steps page.
Fig. 8. The Next steps page.

It is recommended that you configure your SPF record and Exchange Online connectors now, according to the instructions displayed (Fig. 8.). See the articles below for step-by-step instructions.

When your mail flow is configured, the Next steps page (Fig. 8.) will explain how to create your first email signature rule.

Client-side mode provisioning

If you choose the client-side signature mode in step 4. of the tenant registration wizard (see Fig. 5.) and click Register, the tenant is registered and provisioned right away.

You now need to deploy either of the two Outlook signature add-ins to people who will be using CodeTwo email signatures in Outlook:

However, since you have not created any signature templates yet, it's better to prepare them first - follow the steps provided in this article to create client-side email signature rules. 

Combo mode provisioning

If you selected the combo mode in the tenant registration wizard (see Fig. 5.) and clicked Register, the provisioning includes both:

Use the links above to learn about both of these provisioning processes and the steps you need to follow to start using email signatures in these modes.

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