I am filling out an application on a website. After I'm done filling it out, it asks me to attach my resume or any other pertaining documentation. When I click on it, the only choice I get in from the Camera Roll. There has to be a way to go to Pages and choose the document that I want.
No, not yet sorry. During the WWDC Keynote they announced "iwork for icloud" that will allow you to access pages from a web browser. However this isn't available to the public, you could email your pages document to yourself as a PDF or word document and open it with another program.