Magento provides so many default fields but If we need custom information in customer address then we can create a new customer_address type attribute.

In this article, I will share how we can add text type attribute in Customer Address,

You need to create InstallData.php file in your existing module or you can create a new module as well as,

If you are creating in your existing module: app/code/[Vendor Name]/[Module Name]/Setup/InstallData.php

<?php
namespace [Vendor Name]/[Module Name]Setup;
 
use MagentoCustomerSetupCustomerSetupFactory;
use MagentoEavModelEntityAttributeSet as AttributeSet;
use MagentoEavModelEntityAttributeSetFactory as AttributeSetFactory;
use MagentoFrameworkSetupInstallDataInterface;
use MagentoFrameworkSetupModuleContextInterface;
use MagentoFrameworkSetupModuleDataSetupInterface;
 
class InstallData implements InstallDataInterface
{	
	/**
     * @var CustomerSetupFactory
     */
    private $customersetupFactory;
 	
 	/**
     * @var AttributeSetFactory
     */
    private $attributesetFactory;
 	
 	/**
     * @param CustomerSetupFactory $customersetupFactory
     * @param AttributeSetFactory $attributesetFactory
     */
    public function __construct(
        CustomerSetupFactory $customersetupFactory,
        AttributeSetFactory $attributesetFactory
    ) {
        $this->customersetupFactory = $customersetupFactory;
        $this->attributesetFactory = $attributesetFactory;
    }
 
    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
 
        $customerSetup = $this->customersetupFactory->create(['setup' => $setup]);
        $customerEntity = $customerSetup->getEavConfig()->getEntityType('customer');
        $attributeSetId = $customerEntity->getDefaultAttributeSetId();
        $attributeSet = $this->attributesetFactory->create();
        $attributeGroupId = $attributeSet->getDefaultGroupId($attributeSetId);
 
        $customerSetup->addAttribute('customer_address', 'job_title', [
            'type' => 'varchar',
            'label' => 'Job Title',
            'input' => 'text', //You can change your input type as per your requirement
            'required' => false, //If You need this field is required in customer address area then you can just set "true" in stand of "false"
            'visible' => true,
            'user_defined' => true,
            'sort_order' => 1000,
            'position' => 1000,
            'system' => 0,
        ]);
 
        $attribute = $customerSetup->getEavConfig()->getAttribute('customer_address', 'job_title')
            ->addData([
                'attribute_set_id' => $attributeSetId,
                'attribute_group_id' => $attributeGroupId,
                'used_in_forms' => ['adminhtml_customer_address'], //Other list of forms: customer_address_edit, customer_register_address where you want to display the custom attribute 
            ]);
 
        $attribute->save();
    }
}

After creating the above file you have to run below commands:

php bin/magento setup:upgrade
php bin/magento cache:clean

Now you can check in the customer section in the admin area.
Our newly created attribute shown in the customer address form.