If you are looking to register an app for Power BI I would recommend following the guide:
To use Power BI embedded analytics, you need to register an Azure Active Directory (Azure AD) application in Azure. The Azure AD app establishes permissions for Power BI REST resources, and allows access to the Power BI REST APIs.
Set up Power BI Embedded
https://learn.microsoft.com/en-us/power-bi/developer/embedded/register-app?tabs=customers
You can register here:
Register your application for Power BI
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