Use Widget signing in electronic workflow

We need people to sign waivers as part of the sign-up process for events. Ideally, our system would present the waiver (via Adobe), the person would sign it, our system would receive confirmation that it's complete, then the process could proceed to the next step. We don't know in advance who will sign up, so a Widget seems to be the way to go, but we're not sure how we might do this with what we can see in the current API docs. Is there a way to do this with the API?