Looking for apps/systems that allow me to have clients fill out forms electronically

Hello, I would recommend Survio.com. I find it easy and user-friendly. You create the form in few steps, you share it by e-mail, Facebook, or through your website and gather the registrations and have them arranged in clear graphs in real-time. http://www.survio.com

There are many solutions for this. One of my favorites is JotForm. They have free and paid subscription options plus HIPAA compliant templates you can edit or build your own form from scratch. Their forms are optimized for mobile and you can embed them in your website or use easy to share links.