By default, the message list has columns with the following headings: an envelope icon indicating whether you have read or replied to a message, an exclamation point indicating priority, and the From, Subject, and Date fields. You can change their order and remove them by dragging and dropping them. To add columns:
Right click on the column header
Click Add a Column
Click and drag a column you want into a space between existing column headers. A red arrow will show you where the column will be placed.
Right-click on one of the column headers to get a list of options:
Sorts the messages top to bottom.
Sorts the messages bottom to top.
Groups messages instead of sorting them. This makes each contact with identical properties in the specified field to be placed in its own group and physically separated from others.
Remove this column from the display. You can also remove columns by dragging the header off the list and letting it drop.
When you choose this item, a list of column headers will appear; just drag and drop them into place between two existing headers. A red arrow will appear to show you where you're about to put the column.