GoodReader is a paid app for iOS that belongs to the category Productivity, and has been developed by Yuri Selukoff. It's recommended for students, college students, teachers, academics, grad students, lawyers, knitters, gamers.
More about GoodReader
People say as a musician this is my preferred app for sheet music, to transfer files to box and dropbox and to my laptop, as well as highlighting and note taking options.
If you like GoodReader you'll also enjoy: PDF Expert - Fill forms, annotate PDFs, sign documents, ReaddleDocs (documents/attachments viewer and file manager), iAnnotate PDF, GoodReader for iPad, FileApp ( File Manager & Document Reader ), Dropbox.