What is the purpose of the Post Master address, and How will you configure it in Office 365?
The postmaster address in Office 365 is used for sending system-generated messages and notifications all to recipients who are outside of your Microsoft Exchange Online organization.
You need to use the Exchange Online Powershell to configure a postmaster address. Here’s how to set a postmaster address in office 365:
Use this syntax in Powershell and mention the email address you want to set as the postmaster:
Set-TransportConfig -ExternalPostmasterAddress <emailaddress></emailaddress>