Thank you for posting this in Microsoft Q&A.
I understand you don't want the users to get an invitation mail of being added in a group of Microsoft entra id.
Unfortunately, In Power Automate, there is no way to stop notifications once a user is added to any Microsoft enterprise ID group.
There is one way to achieve this using PowerShell.
For your reference: Turn off group welcome email
Hope this helps. Do let us know if you any further queries.
Thanks,
Navya.
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