One of the justifiable criticisms of the iPad was that it was difficult to impossible to transfer files between many apps or networks. With the addition of some apps like PocketCloud and FileBrowser, and the improvement of the Open in… function in later systems , especially iOS 6, this has become even less of an issue. Still, in terms of downloading files on web based apps, you were often limited to photos from the camera roll. This was the case with the Edmodo app.
Via shm, Jennifer Walker