The very first thing you need to know what is PDF. PDF stands for Portable Document Format. A PDF file can be read anywhere just by using PDF viewer. To view PDF file, there are several programs available over the net. The most interesting thing is that the almost all PDF viewers are free of charge!!
Which one should I use? Good question.
You can use any of the two. If your disk space is low, then use Foxit Reader. But if you have more disk space use Adobe Reader. With adobe reader you will find some more options. Nothing else.
You can convert your file into PDF from several program. For example, you can convert a file into PDF from MS Word, Excel, Power Point and so many. When you convert a PDF file into word, then you can use it in a computer where MS Office Program is not installed. In that case, you need a PDF viewer.
Click here to know how to create PDF file.