$now = time(); // OR USE strtotime(string date) to get the timestamp for a formatted date
$daystoadd = 5;
$timetoadd = $daystoadd * 86400; // seconds per day for each day you want to add
$futuredate = date("F, d Y G:i:s a",($now + $timetoadd));
// DISPLAY IT
echo $futuredate;