I'm trying to download a PDF from the child support website it is saying I'm trying to open it in acrobat and say I need Acrobat 8 or more and what do I do to get that because I need that it's important

I need to download a form from domestic Relations it's very important for my case I tried to open it with acrobat Adobe my acrobat and it's saying I need eight or more update I guess I don't know how do I get that update and how much is it going to cost me because I'm sure there's a cost on it and I need it very soon because it is very important that I get paid