Android App and Web Server Communication

I am having a website superdealhub.com, everything is working fine here. Now I want to launch an android app from the same. Kindly help me with just 1 point, suppose i will create a signup page for the users in the app, and after the user filled the form and hit the signup button, the data should be stored in the same web server of superdealhub.com.

Just help me with that. rest i can handle. Thank you so much.