Hi @Vinod Survase ,
How to add Mail Enabled Security Group in Outlook client like distribution group or M365 group?
Do you mean you want to make mail-enabled security groups show up under Groups in the left nav pane of Outlook?
If this is the case, I am afraid it's currently not feasible for mail-enabled security groups. You can posting a feature request to the dedicated feedback portal for Outlook via: https://feedbackportal.microsoft.com/feedback/forum/89a8afa3-2e1c-ec11-b6e7-0022481f8472
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