Problem
You wish to configure Signature 365 integration with your Microsoft 365 tenant, and do not wish to enable external connectors.
Information
Signature 365 can easily be configured in read only mode as part of the initial integration process, requiring only the permissions detailed at the bottom of this article.
We recommend creating and using a mail-enabled security group to manage users and groups that have access to Signature 365, as detailed in Restrict access to Signature 365 using an Office 365 Security group : Signature 365 Help Center.
Whilst read only permissions for your directory and users are required to integrate with Signature 365, all other permissions for the service are not required if you wish to test the software, or run in client-side only mode.
In this mode, no changes are made within Exchange Online, and no emails are routed through the Signature 365 servers.
Solution
To configure Signature 365 in this manner, complete the following steps.
Create your Signature 365 tenant by following the steps in Signing up for a Signature 365 account : Signature 365 Help Center
From the main portal screen, click the Setup button on the banner titled Finish setting up your account.
Click Next on the Siganture 365 setup screen.
Select Apply only to email when composing in Outlook Clients (client-side) and select Next.
Click Authorise to grant the Signature 365 application access to read users groups and dominas from your Microsoft 365 tenant. This will redirect you to the Microsoft login system, you must log in using an account with Global admin privileges to grant this access.
Review the requested permissions and click Accept to continue.
You will now be able to select the users and attributes you want to import into Signature 365. You can choose to import all users from Azure Active Directory, or specific groups of users via mail-enabled security groups.
Click the Add Group button to select the groups you want to import, and click Next to continue.
The following page will be displayed detailing how to install the Signature 365 add-in for Outlook. Once you have reviewed the page, click Complete setup to proceed, and Go to dashboard to return to the dashboard
Signature 365 will now import the users you have selected, and will be running with read only access to your Microsoft 365 tenant.
Information
Integration of Signature 365 requires an account with permission to grant permissions to applications.
Typically this means that a Global Administrator account will be required, this can also be configured by creating a custom directory role with permission to grant permissions to applications.
Required permissions for reading directory data
The permissions in this section are always required to integrate with Microsoft 365.
The permissions below are required to import directory, user and group information:
Read directory data
This allows us to import your directory, including users, groups and domains.
Read all users' full profile
This allows us to import your users and profiles for use in your signatures.
Read all user mailbox settings
This allows us to import your users' mailbox settings.
Sign in and read user profile
This is required to connect to your tenant.