woocommerce add custom checkout field to email

You should use 'My Field' instead of my_field. As you have saved the custom field with this key. This will definitely solve your problem.

I had similar trouble of printing the result until I added an underscore before 'my_field'.

So use

add_filter('woocommerce_email_order_meta_keys', 'my_custom_checkout_field_order_meta_keys');function my_custom_checkout_field_order_meta_keys( $keys ) {    $keys[] = '_my_field';    return $keys;}

it seems when woocommerce is querying the meta data for use in admin section, an underscore is added. So for a field you created as

    add_filter( 'woocommerce_checkout_fields' , 'brown_remove_billing_postcode_checkout' );function brown_remove_billing_postcode_checkout( $fields ) {    // Add New Fields    $fields['billing']['billing_delivery_date'] = array(        'label'     => __('Delivery Date', 'woocommerce'),        'placeholder'   => _x('yyyy-mm-dd', 'placeholder', 'woocommerce'),        'required'  => true,        'class'     => array('form-row-wide'),        'clear'     => true,        'autocomplete' => false     );//Update the order meta with field value. Don't miss the underscore before _b$fields['billing_delivery_date'] = get_post_meta( $order->id, '_billing_delivery_date', true );    return $fields;}

You need to add to your functions.php

/*----------------------------------------------    Add Delivery Date Field to the order emails-------------------------------------------------*/add_filter('woocommerce_email_order_meta_keys', 'my_woocommerce_email_order_meta_keys');function my_woocommerce_email_order_meta_keys( $keys ) {    $keys['Delivery Date'] = '_billing_delivery_date';    return $keys;    }