Custom field on EDIT ADDRESS page

Hi everyone,

first of all I would like to congratulate you, it is the first time that I need help on the forum , as the community and your guides are full of resources. Anyway, there’s always a first time, since i’m not an expert ??

I’m using the code below to show a custom billing field on my checkout page, and it’s working very well. Also it is stored in the woocommerce order, as expected.

My question is: Why can’t I edit/save it in the edit address page, but I can do it for ex. with the phone field?

I’m certainly missing something, is there a hook I can use or something?

Thanks in advance,
Best regards

// My custom field
	add_filter( 'woocommerce_checkout_fields' , 'field_cfpiva' );

	function field_cfpiva( $fields ) {
		 $fields['billing']['billing_cf'] = array(
			'label'     => __('Codice Fiscale / P.IVA', 'woocommerce'),
			'placeholder'   => _x('Codice Fiscale / P.IVA', 'placeholder', 'woocommerce'),
			'required'  => true,
			'class'     => array('form-row-wide'),
			'clear'     => true
		 );

		 return $fields;
	}

	add_filter( 'woocommerce_admin_billing_fields' , 'admin_field_cfpiva' );

		function admin_field_cfpiva( $fields ) {
			 $fields['cf'] = array(
				'label' => __('Codice Fiscale / P.IVA', 'woocommerce'),
				'show'	=> true
			);
			return $fields;
		}

https://www.ads-software.com/plugins/woocommerce/