iOS iPad app where I can annotate PFD documents within my app

I am developing an iOS app for an iPad. It's a paperless meeting app. The documents are in PDF. Loaded via the web admin and pushed to the iPad app. I want the meeting members to be able to annotate and mark up the PDFs (highlight, make notes, etc and save them back to there App. see example [login to view URL] I need this all to happen within the App environment. We need to know how to do this (either though coding, an API, etc). Here's an example, go to 45 secs into video [login to view URL] or this [login to view URL]