Requirements
To create and test a single-tenant application that uses server-to-server authentication you will need:
An Azure AD tenant to use when registering the provided sample application.
A Dataverse subscription that is associated with the Azure AD tenant.
Administrator privileges in the Azure AD tenant and Dataverse environment.
To create an unlicensed "application user" in your environment, follow these steps. This application user will be given access to your environment's data on behalf of the end user who is using your application.
Navigate to your Dataverse environment (https://[org].crm.dynamics.com).
2. Navigate to Settings > Security > Users.
3. Choose Application Users in the view filter.
4. Select + New.
5. In the Application User form, enter the required information.
6. In the Application ID field, enter the application ID of the app you registered earlier in Azure AD.