Do any of the following:
Preview the first three lines of messages in the main Outlook window
Note To preview the first three lines of unread messages only, on the View menu, point to Current View, and then click Customize Current View. Click Other Settings, and then click Preview unread items.
Preview the content of any item in the preview pane
In the preview pane, you can read the content of an item, open attachments, follow a hyperlink, and respond to meeting requests.
To hide the preview pane, repeat this step.
Note When you're viewing a message in the preview pane, you can view e-mail properties about a name in the From, To, or CC fields by double-clicking it.
For Help on an option, click the question mark, and then click the option.