_redirect()
This function is used for between Magento modules.
<?php $this->_redirect('module/controller/action');
example:- $this->_redirect('customer/account/create');
?>
We can redirect within our current controller by specifying ‘*’.
<?php $this->_redirect('*/*/add'); ?>
Note:- first * is used for module and second * is used for controller.
_redirectUrl()
This function is used for external URL or outside Magento base.
<?php $this->_redirectUrl('http://google.com'); ?>