Receive a Secure Application

I have a client that wants to upload an application to their site for potential employees. This document will be asking for personal information like social security numbers. My client wants all personal information to be secured/encrypted once it's been entered by the applicant—there is a submit button and signature field on the PDF. My coding skills are limited—to say the least—and I'm not sure how to go about securing information that is being entered by another party and being forwarded on.

Any help would be appreciated!

Thanks!