We’re happy to help. Please try these instructions. If that does not help, please reply to this ticket within the Help Desk application with three days to reopen it.

https://answers.microsoft.com/en-us/outlook_com/forum/all/add-a-button-to-report-phishing-emails-in-outlook/44e8427a-28aa-416d-a701-119fb2558705

You can add the report as Phishing option by following these steps:

1. On your Outlook app, right click on the Home tab and select Customize the Ribbon. 
2. Under the Choose commands from, select All Commands. 
3. Select Phishing, click Add and hit OK.