Step1: Create a file addCustomerColumn.php file in root directory
and put the below content in that file.
<?php
require_once('app/Mage.php');
Mage::app()->setCurrentStore(Mage::getModel('core/store')->load(Mage_Core_Model_App::ADMIN_STORE_ID));
$installer = new Mage_Sales_Model_Mysql4_Setup;
$installer->addAttribute('customer_address', 'extra_field', array(
'type' => 'varchar',
'input' => 'text',
'label' => 'Extra Field',
'global' => 1,
'visible' => 1,
'required' => 0,
'user_defined' => 1,
'visible_on_front' => 1
));
Mage::getSingleton('eav/config')
->getAttribute('customer_address', 'extra_field')
->setData('used_in_forms', array('customer_register_address','customer_address_edit','adminhtml_customer_address'))
->save();
$installer->endSetup();
?>
Note: Change Extra filed name to your desire custom name.
Step2: Now run this file on your browser.
Step3: Clear your project cache.