Acrobat Reader is used to open many documents at Wharton. You'll need a recent copy of the reader, which you can download and install for free at http://get.adobe.com/reader/.
If you are using recent versions of Microsoft Office, you can create a PDF file with most applications just by saving the document you're working on. For instance, if you are using Word, you can save the file as a .pdf file.
From the Application, Choose "Save As"
(This option can often be found under the File tab)
Choose the file extension available to specifically create a .pdf file
For more information on saving documents as .pdf files, consult the help documentation of your application.