wco-add-checkout-field

```php
/**
 * Add form fields to Checkout
 */
add_filter('woocommerce_checkout_fields', 'wmco_woocommerce_checkout_fields');
function wmco_woocommerce_checkout_fields($fields){
    $new_field['billing_org'] = [
		'label'     => __('Org no.', 'woocommerce'),
		'placeholder'   => _x('Org no.', 'placeholder', 'woocommerce'),
		'required'  => false,
		'class'     => array('form-row-wide'),
		'clear'     => true
    ];
	array_splice( $fields['billing'], 4, 0, $new_field );
	return $fields;
}


/**
 * Display field value on the order edit page
 */
add_action( 'woocommerce_admin_order_data_after_shipping_address', 'wmco_woocommerce_checkout_fields_order_edit', 10, 1 );
function wmco_woocommerce_checkout_fields_order_edit($order){
	echo '<p><strong>'.__('Org no.').':</strong> ' . get_post_meta( $order->get_id(), '_billing_org_no', true ) . '</p>';
}
```
Adjust the value 4 in `array_splice()` to set the order of the new field.