>>If the action forwards the call to another action:

$this->forward('store', 'index');

forward is internal to the applicaton

>> If the action results in a web redirection:

$this->redirect('store/index'); $this->redirect('http://www.google.co.in)

redirect is internal to the application as well as we can redirect to external urls also

when you submit a form with post method use redirect, because if the user refreshes the page, form will not be submitted again