In Outlook
Open the mail in outlook (at least in the read panel)
A new button is available in your toolbar: "the report message". Click on it
Based on the content of the message, select of it's pure spam (junk) a phishing attempt or "not junk" if you estimate is was incorrectly flagged as spam.
In Outlook on the web
Open the mail in outlook in the read panel
Click on the 3 dots icon and select the appropriate option
If you have opened the mail in full screen, the option "junk" is also available in the toolbar.
