Add custom fields to order

//* Add select field to the checkout page
add_action('woocommerce_before_order_notes', 'barbareshet_add_select_checkout_field');
function barbareshet_add_select_checkout_field( $checkout ) {
    $current_user = wp_get_current_user();
    if ( !user_can( $current_user, 'administrator')) return;
    woocommerce_form_field( 'order_method', array(
        'type'          => 'radio',
        'class'         => array( 'barbareshet-drop' ),
        'label'         => __( 'Order Method', 'oceanwp-child' ),
        'options'       => array(
            'online'    => __( 'online', 'oceanwp-child' ),
            'phone' => __( 'by phone', 'oceanwp-child' ),
        )
    ),

        $checkout->get_value( 'order_method' ));

}

// save custom field values

function barbareshet_save_order_cf( $order_id ){

    if( !empty( $_POST['order_method'] ) )
        update_post_meta( $order_id, 'order_method', sanitize_text_field( $_POST['order_method'] ) );

}
// save fields to order meta
add_action( 'woocommerce_checkout_update_order_meta', 'barbareshet_save_order_cf' );

function barbareshet_checkout_field_display_admin_order_meta($order){
    echo '<p><strong>'.__('Order Method', 'oceanwp-child').':</strong> <br/>' . get_post_meta( $order->get_id(), 'order_method', true ) . '</p>';

}
add_action( 'woocommerce_admin_order_data_after_billing_address', 'barbareshet_checkout_field_display_admin_order_meta', 10, 1 );