Steve, you create the form as PDF and Word and save them somewhere.

(1) You then drag the PDF onto your page and select Add Link.
If you select your PDF icon so created, you can then click Edit Widget and open the Placeholder code (body) and you will find the link to the PDF file.
e.g., <a href="index_htm_files/2014-11-27000000.pdf"><img src="http://webdesigner.xara.com/pdficon_large.png" border="0"></a>.
You would copy this link to your Form (PDF) button as its link.
You then remove the PDF icon.

(2) A Word file, or most others, is a different approach.
Add a box to your page.
Select it and press Ctrl+Alt+Shift+A and in the dialog box find the required file and click OK.

(3) You can automate it a bit more by using Link > Link to file (PDF, AVI, etc) in its Web Properties.
I don't use this normally as it creates a genuine link.

You would then compose the link for your Form (Word) button as index_htm_files/<Word File Name.docx>.
Unfortunately, you have to keep the box on your page; I usually hide it underneath something.
I find this to be a poor design approach and I hope there is a better solution form Xara or another TGer.

Acorn

P.S. Just realised that if you have the buttons already, the third approach is exactly what you want for either the PDF or MS word file!!!