WC customising checkout fields using actions and filters - Lesson 3 snippet 4

gistfile1.php

/**
 * Display field value on the order edit page
 */
add_action( 'woocommerce_admin_order_data_after_billing_address', 'my_custom_checkout_field_display_admin_order_meta', 10, 1 );

function my_custom_checkout_field_display_admin_order_meta($order){
    echo '<p><strong>'.__('My Field').':</strong> ' . get_post_meta( $order->id, 'My Field', true ) . '</p>';
}

Suggestion for WC3.0+

/**
 * Display field value on the order edit page
 */
add_action( 'woocommerce_admin_order_data_after_billing_address', 'my_custom_checkout_field_display_admin_order_meta' );

function my_custom_checkout_field_display_admin_order_meta( $order ){
    echo '<p><strong>'.__( 'My Field' ).':</strong> ' . $order->get_meta( '_my_field', true, 'edit' ) . '</p>';
}