for populate a filled out value at frontend you can do something like that:
<?php
/*
* Create PHP DateTime object from Date Piker Value
* this example expects the value to be saved in the format: yymmdd (JS) = Ymd (PHP)
*/
$date = DateTime::createFromFormat('Ymd', get_field('date_picker'));
echo $date->format('d-m-Y');
?>
official Datepicker Documentation
or did you wish to prefill a datepicker field?
