Hi Rajat,

  Are you looking for a workflow that allows an anonymous user to create an account? I recommend you check out the 'Forgot Password Module' in the app store.

 This module, on top of having a password reset workflow, has a set of microflows and pages you can use to allow users to sign up. It is a more work than a simple button, of course, but it works well and involves sending an e-mail to confirm the registration to prevent account creation spam.