DateTime::add() php code example
Example 1: php date plus days
<?php
// PHP program to add days to $Date
// Declare a date
$date = "2019-05-10";
// Add days to date and display it
echo date('Y-m-d', strtotime($date. ' + 10 days'));
?>
Example 2: add 6 months to date in php
$effectiveDate = date('Y-m-d', strtotime("+3 months", strtotime($effectiveDate)));