To manage your info you have a comment field. You can drop in it whatever you want email (it will link the task to the email) files (it will create an alia or a copy of the file, you can even write notes in it. I personally do all this i manage all my stuf in OF which is a kind of central software of all my datas on my computer. I also add many notes and comment about things including checklist, summaries about GTD, Reference doc, and doc about my projects. It took me time to make my own organization (about 2 years) but now it works perfectly. May be you may take ideas from david allen last book making it all work and the omnifocus free GTD manuel.