Preview items without opening them by using the Reading Pane — just click the item to display its contents. In the Reading Pane, you can view or open attachments, follow a hyperlink, use voting buttons, view the follow-up information in the InfoBar, and respond to meeting requests .
Security Note: Messages viewed in the in the Reading Pane are safe. Potentially malicious scripts or attachments are not activated or opened automatically in the Reading Pane. Although Outlook blocks most malicious attachment types, messages and attachments from unknown or unsolicited senders should always be opened with caution.
On the View tab, in the Layout group, click Reading Pane, and then click Right, Bottom, or Off.