How can M365 Users Report Spam from Webmail

In Microsoft 365 organizations with mailboxes in Exchange Online, you can use the built-in reporting options in Outlook on the web (formerly known as Outlook Web App) to submit false positives (good email marked as spam), false negatives (bad email allowed) and phishing messages to Exchange Online Protection (EOP). 

Microsoft AntiSpam AI will AutoLearn from the Feedback and update the reported patterns in MS Exchange Online Filter Database.

Report spam and phishing messages in Outlook on the web

1. For messages in the Inbox or any other email folder except Junk Email, use either of the following methods to report spam and phishing messages:

   • Select the message, click Junk on the toolbar, and then select Junk or Phishing.

     

   • Select one or more messages, right-click, and then select Mark as junk.

2. In the dialog that appears, click Report. If you change your mind, click Don't Report.

   

   

3. The selected messages will be sent to Microsoft for analysis. To confirm that the messages have been submitted, open your Sent Items folder to view the submitted messages.

Report non-spam and phishing messages from the Junk Email folder in Outlook on the web

1. In the Junk Email folder, use either of the following methods to report spam false positives or phishing messages:

   • Select the message, click Not Junk on the toolbar, and then select Not Junk or Phishing.

     

   • Select one or more messages, right-click, and then select Mark as not junk.

2. In the dialog that appears, read the information and click Report. If you change your mind, click Don't Report.

   

   

3. The selected messages will be sent to Microsoft for analysis. To confirm that the messages have been submitted, open your Sent Items folder to view the submitted messages.

Source :  https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/report-junk-email-and-phishing-scams-in-outlook-on-the-web-eop?view=o365-worldwide