To preview PDF-files in Outlook you can install the latest version of Adobe Reader. This includes a preview handler that is compatible with Outlook 2007, Outlook 2010 and Outlook 2013.
Download: Adobe Reader
When you are using Outlook 2013 on Windows 8 or Windows Server 2012 or newer, Outlook has native support for previewing pdf-files. Opening pdf-files via a double click will open it in the Reader app and can even be edited in Word 2013. Installing Adobe Reader has therefor become optional.
Search inside PDF-files
When you are using Windows 7 or previous and want to be able to search inside PDF-attachments in Outlook and Windows, you must install an iFilter for pdf-files. When you are using a 32-bit version of Windows, this is automatically installed when you install the latest version of Adobe Reader.
For a 64-bit version of Windows you’ll need an additional installer which you can download below.
Windows 8 and Windows Server 2012 and later provide native support for indexing pdf-files. This applies to both the 32-bit and the 64-bit editions and is done via the Reader Search Handler. Installing the Adobe PDF iFilter is therefor optional.
PDF iFilter for Exchange, SharePoint and SQL
The 64-bit PDF iFilter also enables searching inside pdf-files in server products such as Microsoft Office SharePoint Server 2007 and 2010, Microsoft Exchange Server 2007 and 2010, and Microsoft SQL Server.
Microsoft Exchange 2013 and SharePoint 2013 include their own PDF iFilter. If you want, you can force it to use the Adobe PDF iFilter in the following way: