PHP - get current date, add years/months/days

get current datetime
$dateTime = new \DateTime('now', new \DateTimeZone('Europe/Dublin'));
echo $dateTime->format('Y-m-d H:i:s');
get current year
$dateTime = new \DateTime('now', new \DateTimeZone('Europe/Dublin'));
echo $dateTime->format('Y');
get current month
$dateTime = new \DateTime('now', new \DateTimeZone('Europe/Dublin'));
echo $dateTime->format('m');
get current day
$dateTime = new \DateTime('now', new \DateTimeZone('Europe/Dublin'));
echo $dateTime->format('d');
add years to date
$dateTime = new \DateTime('2019-09-01 11:12:13', new \DateTimeZone('Europe/Dublin'));
$dateTime->modify('+3 year');
echo $dateTime->format('Y-m-d H:i:s');
add months to date
$dateTime = new \DateTime('2019-09-01 11:12:13', new \DateTimeZone('Europe/Dublin'));
$dateTime->modify('+3 month');
echo $dateTime->format('Y-m-d H:i:s');
add days to date
$dateTime = new \DateTime('2019-09-01 11:12:13', new \DateTimeZone('Europe/Dublin'));
$dateTime->modify('+3 day');
echo $dateTime->format('Y-m-d H:i:s');