Exactly as Dave says.

As an example: The link below is to a pdf document. If you click it (and you have Adobe acrobat reader installed on your machine) it will load up and open the file within IE.
http://www.carlocks.com/pdf/us_ford.pdf

If you don't then the reader is freely available from here: http://www.adobe.com/products/acrobat/readstep2.html

So the only thing to worry about is wether the terminals that are going to be used to view the documents have the reader installed.