Embedding power BI report(Embed for organization) using service principle

Hi mstt,
Thanks for reaching out to the Microsoft fabric community forum.

In an Embed for Your Customers solution, your web app must determine the Power BI content that each user can access. To manage this, use the Embed Token REST API to generate an embed token, defining:
1) The specific Power BI content the web app user can access.
2) The user's access level (view, create, or edit).

Please check out this reference article on how to generate access token using Embed for Organization:
Permission tokens needed to embed a Power BI app - Power BI | Microsoft Learn

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Thanks and Regards