So you can't open pdf files?
Yes you can but you may need some help
In olden days, about 1995, you could not read a file (document) on a computer unless you had the same software program the sender had created it in.
Then, as if by magic, pdf (Portable Document Format) was invented. Anyone in the world could open and read a pdf file which is a ‘snapshot’ of the file the sender created in whatever software they chose. It just needed one little program, Adobe Reader, downloaded, free, to your computer. Simple!
If that was simple, today it is ultra simple as PDF readers are built in to all the recent internet browsers whether you use Edge, Chrome, Internet Explorer, Safari, Firefox or any other, on whatever your choice of device is. You now have no downloading or installing software.
If you cannot open a pdf file there is something wrong with the way it looks for the pdf reader in your internet browser and so it can be easily fixed. You just need to ask for some help to configure it correctly.
Editable pdfs (you can open and change them) or Interactive pdfs (you can fill certain bits in yourself), depending on what the sender decides, are now available. Desktop PCs and Laptops are fully compatible with these types but tablets and smart phones are more limited.