Interactivity with PDFs within CoachAccountable completely depends on what sort of PDF viewer someone has in their browser.
Elements of an Interactive PDF such as videos and audio may or may not work depending on the device, browser, and PDF reader the person is using. You're free to upload the PDFs to CoachAccountable, but let clients know that they are best viewed in the latest version of Adobe Acrobat Reader.
Thus, your clients would have to (1) download and install Adobe Acrobat Reader on their device, (2) download the Interactive PDF from CoachAccountable, then (3) open it up with Adobe Acrobat Reader.
If you're instead looking to have a fillable PDF, choose to use a CoachAccountable form-based Worksheet instead. That way, the client can fill out the form quickly and easily on any device (PDFs are notoriously difficult to fill out on mobile devices, whether using CoachAccountable or not). And you can then run reports on their answers.
Similarly, sharing video and audio is best done in CoachAccountable as embedded media, as Files or within a Worksheet or Course, so that clients can view/listen easily.