“wpcargo_after_metabox_section” action hook is use to add additional section after the shipment information section.

Copy and paste this sample code in the theme functions.php file

function my_custom_after_metabox(  ){
    global $post;
    // Get Save post metakey "_shipment_notes"
    $shipment_notes = get_post_meta( $post->ID, '_shipment_notes', true );
    ?>
    <section class="col-md-6">
        <h3 class="section-title wpccf_section_header">Additional Information</h3>
        <div id="form-notes" class="form-group ">                 
            <label for="_shipment_notes">Shipment Notes</label>
            <textarea id="_shipment_notes" class="md-textarea form-control _shipment_notes" name="_shipment_notes"><?php echo $shipment_notes; ?></textarea>
        </div>
    </section>
    <?php
}
 
add_action( 'wpcargo_after_metabox_section', 'my_custom_after_metabox', 99 );