Most of the answers have been covered.
1. If you have choice to download MS Word file, it’s the easy way. You can edit it as you want.
2. If you want to convert MS Word file to pdf after editing, you may download this save as pdf add-in for Office 2007. Download it and run it; it will add “Save as pdf/xps” option to MS Office 2007.
3. If you want to edit pdf, here you can find Foxit. Get Foxit pdf editor and Foxit pdf reader from there.
4. However, if you have older version of MS Office, you can convert word file to pdf from online utilities. You can google it and find many. Here are two: Word to pdf, pdf to word. There are also online utilities which ask you to upload file, and either give file directly to download or email it to you.
With pdf filler, you may upload your pdf file, and fill it online.
Here’s How to create pdf forms.
You can also try 14 days trial of this; here are their free products.
And unfortunately, if nothing works, you may upload the file and give us the link, someone will definitely come out with the solution.