Add months, days, years to PHP date()

date.php

//found on https://snipplr.com/view.php?codeview&id=10958
$date = date("Y-m-d");
$date = strtotime(date("Y-m-d", strtotime($date)) . " +12 month");
$date = date("Y-m-d",$date);
echo $date;

Other examples
$date = strtotime(date("Y-m-d", strtotime($date)) . " +1 day");
$date = strtotime(date("Y-m-d", strtotime($date)) . " +1 week");
$date = strtotime(date("Y-m-d", strtotime($date)) . " +2 week");
$date = strtotime(date("Y-m-d", strtotime($date)) . " +1 month");
$date = strtotime(date("Y-m-d", strtotime($date)) . " +30 days");