We have workflow in the ribbon that uses a Flow to create an email.
An example of an email created is shown below.

The email is sent to an external client.
The question is what email address should be specified in the "TO" address?
We have been told that in order to send an email on behalf of the user, the "TO" address must be a Dynamics 365 user with a mailbox.
Does it have to be a D365 user?
Can it be a shared mailbox?
If it is user, I can set the "Email on behalf of some" in the User Setting but for a shared mailbox, I can't turn that specific setting.
Is there another way to send that email without specifying a D365 user in the "TO" address?
Note that we Server Side Synching and D365 App for Outlook.
a2z