@ivan
In your code, just remove ['billing']
or ['shipping']
after $fields
add_filter( 'woocommerce_shipping_fields' , 'custom_override_shipping_fields' );
function custom_override_shipping_fields( $fields ) {
$fields['shipping_address_1']['label'] = 'Shipping Location in the Philippines';
$fields['shipping_address_2'] = array(
'placeholder' => "Subdivision / Barangay / Municipality",
'required' => true
);
$fields['shipping_city'] = array(
'label' => "City",
'placeholder' => "City",
'required' => true
);
return $fields;
}