GoodReader is a featured app because it is the best app that combines local file management, PDF annotation, and remote file transferring.  Renaming files, creating  local folders, moving files between folders, opening a variety of app file types, and password file protection are a few of the local file management features.  Highlighting text, adding notes, diagram symbols, bookmarks are a few of the PDF markup features.  Transfer files via WebDAV, FTP, or Cloud services. GoodReader is a paid app that only works on an iPad, iPhone and iPod touch.