Below are the meta keys which has been used for storing delivery date and time into the "wp_postmeta" table.

1. For Delivery Date: You can get this either by Delivery Date field label set in the plugin's setting or '_orddd_timestamp' meta key which stores the delivery date in timestamp format.

2. For Delivery Time: You can use " _orddd_time_slot " meta_key which stores the selected time slot in 24 hours format.

For example:

get_post_meta( $order_id. 'Delivery Date', true); or

get_post_meta( $order_id, '_orddd_timestamp ', true ) // you will get the timestamp of the delivery date which you will have to convert into a date.

Also, we do provide a function in our plugin which can be used to obtain the selected Delivery Date and Delivery Time information for any particular order. The functions are as follow:

1) orddd_get_order_delivery_date(): To obtain Delivery Date information for any particular order.

Example: 

$order_id = 123; /*sample order ID*/

$orddd_class = new orddd_common();

$delivery_date = $orddd_class->orddd_get_order_delivery_date($order_id);

2) orddd_get_order_timeslot() function: To obtain Time slot information for any particular order.

$order_id = 123; /*sample order ID*/

$orddd_class = new orddd_common();

$time_slot= $orddd_class->orddd_get_order_timeslot($order_id);