Hi!..

I´m trying to program an e-learning software where user connects to a remote server, this program is a downloadable client "Student".
There will be another application called "Instructor", the instructor can create contents so this will be rendered into the "Students" program.

For example:

Instructor creates a new module where attach an image, audio and some text, clicks on save button, this content will upload into a server.
Student next time logging in will see this new content in his application.

I know an easy way to port the content, is just using PDF documents, so instructor generates it and upload, then student in background download it and renders
But I´m wondering if there is another way to share it, I mean something more private..

Is there any alternative to pdfs?
Thanks