User Creation Callback

// define the woocommerce_created_customer callback 
function action_woocommerce_created_customer( $customer_id, $new_customer_data, $password_generated ) { 
    // make action magic happen here... 
};
// add the action 
add_action( 'woocommerce_created_customer', 'action_woocommerce_created_customer', 10, 3 );