Well @MikeInCairns
is what I replied to you yesterday, maybe you haven't seen it. However, I don't know if the post is about Outlook for Office 365 Outlook or Outlook.com.
About you question, if you notice, for every action/trigger that you create you sign in with an account, so you have to collect the user credential of the account (if not yours) to correctly fill the "from" field; maybe, you could create a generic account (for example, we use a shared mailboxes) if you haven't the credential of that people.
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Regards,
Marco Mangiante