create link to download file
It sounds like you're looking for the PDF Reader module. 


  PDF Reader will render your entity file fields with the selected PDF
  renderer.
  
  The implemented PDF renderers are:
  
  
  Google Docs Viewer 
  pdf.js - PDF Reader in JavaScript 
  Direct PDF embed
  Microsoft Office Web Viewer(7.x-2.x-dev)
  


This module lets you specify any file field to render as a PDF embedded in a node. It also has an option to display download link for the embedded PDF.