All files are sent using PDF format. Virtually all computers these days have pre-installed Adobe Reader software on them. If your particular desktop, laptop, or mobile device does not have a PDF reader of some sort on it, you'll need one to view the items. Adobe Reader is the most common one and it's free. You can download it here.
Can't find your file? Most downloaded files automatically go to the Downloads folder on both Mac and PC. On the Mac, click on the Finder icon in your dock and click on Downloads to see what you've downloaded recently. On the PC, look under My Computer or search the title of the file on your computer for where it could be hiding.
I'm not a computer techie person. The suggestions above sum up my knowledge of downloading digital files. I'm sorry, but I won't be able to provide additional tech help with this.