Email Management: Remove Large file attachments

IMPORTANT: Make sure to empty your Trash folder, as its contents count toward your total mailbox size.

Instructions for "New Outlook" 

New Outlook is enabled when the toggle in the upper right corner of Outlook is on.

Follow the steps below:

Select a folder

Change the Filter to Has files (click the filter button)

Change the sort to By Size (click the sort button)

Before:

After: