Creating Additional Format for the Date / Time field

/**

 * Add additional formats for the Time field Format dropdown.

 *

 * @link https://wpforms.com/developers/how-to-create-additional-formats-for-the-date-time-field-time-picker/

 */

function  wpf_dev_date_field_time_formats1 ( $time_formats ) {

        // Displays 2-digit hour, 2-digit minute, and 2-digit seconds

	$time_formats[ 'H:i:s' ] = 'HH:MM:SS';

	return $time_formats;

}

add_filter( 'wpforms_datetime_time_formats', 'wpf_dev_date_field_time_formats1', 10, 1 );