If you already have a registered user in the same Active Directory then you can proceed using the same user credentials, otherwise, follow these steps to create a new user:
Login to the Azure portal.
Search and move to Active Directory service.
In the Add dropdown, select User.
The New user page appears.
Fill in the information and click Create. An overview appears.
Copy and store the User principal name for future use.
In the Add dropdown, select App Registration. The Register an application page appears.
Register the application.
Select Manage > Certificates & secrets to create a client credential and select a new client secret.
Copy and store the Client Secret ID for future use.
Select Manage > API permissions, then select Add a permission and Microsoft APIs > Microsoft Graph.
Select Application permissions, check the Directory.Read.All box and click Add permissions.
Copy and store the Tenant ID for future use.
Copy and store the User principal name for future use.