If you want to configure that only specific users have access to the Microsoft Teams or Outlook Email integration, please follow these instructions:
Microsoft Teams
As an admin, please visit the Microsoft Teams admin center.
You can use app permission policies to control what apps are available to Microsoft Teams users in your organization. You can allow or block all apps or specific apps published by Microsoft, third parties, and your organization. If you block an app, users who have the policy are unable to install it from the Teams app store. You must be a global admin or Microsoft Teams service admin to manage these policies.
Read the Microsoft Documentation
Outlook Email
Depending on which add-in you plan to use, there will be multiple options.
Office Add-in:
To grant apps access for specific users, please check our documentation.
COM Add-in:
If you want to distribute this add-in to your users manually, please follow this instructions.