Eini0815

Hi,

just for information – solved it with a trick:

add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields' );
function custom_override_checkout_fields( $fields ) {
 $fields['billing']['billing_postcode'] = array(              //replace billing_postcode with your custom field name or something ;)
         'label' => __('Postcode', 'woocommerce'),              //replace Postcode with the field label
          'placeholder' => _x('Postcode', 'placeholder', 'woocommerce'),         //replace Postcode with your custom default value
          'required' => false,
          'clear' => false,
          'type' => 'select',
          'class' => array('form-row-wide'),
          'options' => array(
                   'option_a' => __('123456', 'woocommerce' ),
          )
 );
return $fields;
}

With this you only get a placeholder – not a prefilled field (so a customer has to re enter the value).

The placeholder value also works – so I have the correct fields and syntax – but not the default value.