WordPress at a glance
filter is not described

woocommerce_admin_billing_fields filter-hook . WC 1.0

Init billing and shipping fields we display + save.

Usage

add_filter( 'woocommerce_admin_billing_fields', 'filter_function_name_1956' );
function filter_function_name_1956( $array ){
	// filter...

	return $array;
}
$array
-

Where the hook is called

WC_Meta_Box_Order_Data::init_address_fields()
woocommerce_admin_billing_fields
woocommerce/includes/admin/meta-boxes/class-wc-meta-box-order-data.php 41-91
self::$billing_fields = apply_filters(
	'woocommerce_admin_billing_fields',
	array(
		'first_name' => array(
			'label' => __( 'First name', 'woocommerce' ),
			'show'  => false,
		),
		'last_name'  => array(
			'label' => __( 'Last name', 'woocommerce' ),
			'show'  => false,
		),
		'company'    => array(
			'label' => __( 'Company', 'woocommerce' ),
			'show'  => false,
		),
		'address_1'  => array(
			'label' => __( 'Address line 1', 'woocommerce' ),
			'show'  => false,
		),
		'address_2'  => array(
			'label' => __( 'Address line 2', 'woocommerce' ),
			'show'  => false,
		),
		'city'       => array(
			'label' => __( 'City', 'woocommerce' ),
			'show'  => false,
		),
		'postcode'   => array(
			'label' => __( 'Postcode / ZIP', 'woocommerce' ),
			'show'  => false,
		),
		'country'    => array(
			'label'   => __( 'Country / Region', 'woocommerce' ),
			'show'    => false,
			'class'   => 'js_field-country select short',
			'type'    => 'select',
			'options' => array( '' => __( 'Select a country / region…', 'woocommerce' ) ) + WC()->countries->get_allowed_countries(),
		),
		'state'      => array(
			'label' => __( 'State / County', 'woocommerce' ),
			'class' => 'js_field-state select short',
			'show'  => false,
		),
		'email'      => array(
			'label' => __( 'Email address', 'woocommerce' ),
		),
		'phone'      => array(
			'label' => __( 'Phone', 'woocommerce' ),
		),
	)
);

Where in WP core the hook is used WooCommerce

Usage not found.