PHP через 3 дня
$Today=date('y:m:d');
// Declare a date
$date = "2019-05-10";
//if already have time then use this =============
echo date('Y-m-d', strtotime($Today. ' + 10 days'));
//if already have time then use this =============
// add 3 days to date
$NewDate=Date('y:m:d', strtotime('+3 days'));
// subtract 3 days from date
$NewDate=Date('y:m:d', strtotime('-3 days'));
// PHP returns last sunday's date
$NewDate=Date('y:m:d', strtotime('Last Sunday'));
// One week from last sunday
$NewDate=Date('y:m:d', strtotime('+7 days Last Sunday'));
Singh99