Entra AD App Integration for PowerShell

I need assistance creating an Entra AD app registration to integrate Mail.send with Microsoft Entra Graph for sending emails from on-premises via PowerShell.

Requirements:
- Use PowerShell to send emails with attachments
- Set up API integration with Mail.send
- Create a new app registration in Microsoft Entra
- Provide guidance post-setup for learning purposes

Ideal Skills:
- Experience with Microsoft Entra and Graph API
- Proficiency in PowerShell scripting
- Familiarity with API integrations and app registrations


If someone can fullfill the ask I can give a tenant access to access the resources.