Training material for workshops

We deliver workshops for which we produce a workbook for each delegate, containing information relevant to the workshop as well as space to write comments and answers (old fashioned D ring binder with paper).

We would l like to move to digital workbooks. Creating a PDF for delegates to read and write answers on an iPad or laptop is not a problem.

My questions are:

1. What is the easiest way to make sure that all (and only) the delegates download a copy of the workbook on either iPads or laptops?

2. How do we make sure that, once downloaded, the workbook doesn't get copied/sent/distributed any further?

Thanks, Claire