When adding links to documents on your site, it’s always a good idea to upload them as PDF’s when possible, for the following reasons:

• File size is usually smaller once converted into PDF – Converting documents into PDF will usually greatly reduce the overall file size for the document, especially if the document has a large number of images contained within it.
• Content in PDF’s is more difficult to modify – As PDF’s are ‘Read Only’, users are less likely to be able to modify the content and change the price of a school trip for example compared to if the document was uploaded as an editable word document.
• Some users may not be able to view Office 2007 or 2010 documents – Some people using older versions of Microsoft Office (Office 2003 & earlier) may not be able to view documents created in newer versions as the file extensions are slightly different. You can download a patch from Microsoft (around 50mb) which will allow the users to view Office 2007 & 2010 documents, although they might not want to download the patch just to view a document, or they may not know how or have the permissions to download & install the update, meaning they would not be able to view the document.

There are many free programs which you can download  in order to convert documents into PDF including Cute PDF Writer and PDFCreator.

Click here for a guide on how to convert a document into PDF using Cute PDF Writer