Adobe has many different programs to use. For PDF, there are Adobe Reader and Adobe Acrobat.
Adobe Reader is for
viewing PDF files.
Adobe Acrobat is for
editing PDF files.
So, if you want to convert PDF documents into word using Adobe, you should use Adobe Acrobat. (it has free trial time)
Otherwise, you can use some other tools to convert PDF to Word. There are both online pdf to word converter and desktop software. Here is a
review on some pdf to word converters.