IF you have more than one email account or have been given access to an MS 365 Shared Mailbox with "Send As" permissions, you can send out an email using that account as the sender's email address:
Start a new email in Outlook and click on the "Pop Out" option so it is in a new window:
Select 'Options' and ensure the 'From' option in the 'Show Fields' tab is selected:
The 'From' field will now be available as an option at the top of new emails.
Select the 'From' drop-down button and select 'Other Email Address...' :
In the dialog box, enter the other email address that you want to appear as the Sender of the email, and click OK:
This will now also be a default option in the 'From' drop-down for quicker access:
