Office 365 Email makes it easy to block or allow senders right from Outlook.
If you don't use the Outlook desktop application, use these instructions to add email addresses to your list of approved/safe senders or blocked senders.
Note: To edit an entry, click the pencil icon, make your edits, hit Enter or Return, then click Save. You can also click the trash can icon to delete an entry from your Safe senders and domains list or Blocked senders and domains list, then click Save.