
Microsoft Office 365 Administration Cookbook
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This recipe will cover how an admin can prevent external parties from emailing internal Office 365 groups, which can have their own email address and shared mailbox.
You must be a global admin to perform these steps.
Update the -Identity
parameter with the display name of the group you wish to change, and then run the following code snippet:
Set-UnifiedGroup -Identity "Test" -RequireSenderAuthenticationEnabled $true
You've just protected an Office 365 group's inbox from unwanted external emails. Setting the -RequireSenderAuthenticationEnabled
property on a group allows only internal users to send an email to that group. If external users send a message to the group's email address, that message will be rejected. Internal users are still able to send externally, unless other restrictions are put in place.
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