The PDF file format requires an application on your computer to view the downloaded file. These are often already on your computer but if you don't seem to be able to view the PDF file you might need to install Adobe Acrobat Reader. You can find more information about this on the following webpage: http://get.adobe.com/uk/reader/
ePub is an open book format used by Apple iOS devices such as the iPad and iPhone. Use any of the following options to view ePub files on your iPad or iPhone:
The documents will then be available to view in the iBooks app on your device.
Kindle files can be read by any Amazon Kindle device or using a Kindle application on any other mobile device, PC or Mac. You can send Kindle documents to your device by simply emailing them to your personal Kindle email address. The email address from which you send the document must be registered with Amazon.