If the PDF-file is made by a music programm you can use PDFtoMusic. Export to a midi-file and import it in NoteWortyComposer. The text can also be copied. More information at www.myriad-online.com
I use NoteWorthy Composer for studying choral parts for a choir. But publishing in NWC-files is not allowed because there is a copyright. Publishing of midi-files is allowed because it is not printable. That’s why I use then 'Boundary – Start a collapsible section' at the beginning of each staff. Finally I add a blank staff with no lines . If you will print this file, you get a blank page. I think that in this way the users of my website can use the NoteWorthy Viewer without infringe the copyrights. (if my English is not correct, please forgive me, I am Dutch)