Enable/Disable - SSRS Export Types

SSRS supports exporting to different formats when you view the report through a drop-down list. Report services server configuration file which is available in the following path allows to control the list:
C:\Program Files\Microsoft SQL Server\MSSQL.2\Reporting Services\ReportServer\rsreportserver.config

Inside the <Render> tag elements, the Extension names have Visible attribute which changing them to true will make the Extension visible in the Export list.
Example:

Enable/Disable - SSRS Export Types