[development] Web form customization and submit action redirect to custom php code.

Hi, I am developing a website for internal work flow in my organization. I am not sure how to proceed, customization seems very complicated to me. I tried hands on adding custom page, php code, but i m not sure how to redirect webform to a custom php page. Please consider me a newbie. My requirements are: 1. Create a web form. ( with a text and a submit button) 2. get the value of web form text field. 3. process the value through a internal command running on server, display the output. Could you please help me out with these. Thanks and regards, Rohit Sharma