For companies using Exchange Online in Office 365, you can use the Outlook External Sender Tag feature to mark emails coming from outside your organization as "External." To do this, let's connect to the Exchange Online service by typing the following commands in PowerShell one by one.
Set-ExecutionPolicy Unrestricted
Install-Module -Name ExchangeOnlineManagement
Import-Module ExchangeOnlineManagement
Connect-ExchangeOnline
You can use the following command to enable "Outside Company" tagging for all users in Outlook.
Set-ExternalInOutlook -Enabled $true
You can use the following command to check whether the "Offsite" tag action is enabled or not.
Get-ExternalInOutlook
When you enter your mailbox via Outlook Web, you can now see a label indicating emails from external sources.
You can see the label on Outlook in the image below.
We can once again see the marking process in the Outlook application used on the phone.
