Outlook has a default view but you can add additional columns.  For example, the instructions below, will walk you through how to add Size to the view so you can see how large an email is.

1.  While in the Inbox, RIGHT mouse click on one of the titles listed at top.  For
     example, From.
2.  Click on Field Chooser.
3.  From the list, select Size by clicking and dragging to the top of the main 
     toolbar.  Once you have it where you want it, let go of your mouse. 
     The system will drop the field Size where you want it located.

You can change which field you see first, by clicking and dragging the column to where you want it. 

The above steps would have to be completed in any of the folders you are wanting to modify (Sent, Deleted etc).