This is a very general and broad question. I will give you some pointers. I assume by "I would like to know how to make this data secure and prone from hacking," you would like to protect it from tampering, modification and unauthorized access. I will further assume that we are not discussing the physical security of the computer and network, nor are we concerned about denial of service, but are concentrating on digital data security. You'll want to use encryption for the transmission of the data. SSL and, its daughter TLS, provide for confidentiality and integrity. There are software libraries available you can integrate into your software. A search (on searchSecurity.com, for example) should yield some free libraries for testing and commercial products for production. S/MIME is, of course, Secure MIME. If you want to use S/MIME for this, doing a search on "S/MIME library" with Google should get you started.
For more information on this topic, visit these other searchSecurity resources:
Best Web Links: Secure Messaging
Best Web Links: Encryption
Ask the Expert: Encrypting Web forms