The DateTime constructor takes a parameter string time
. $time
can be different things, it has to respect the datetime format.
There are some valid values as examples :
'now'
(the default value)2017-10-19
2017-10-19 11:59:59
2017-10-19 +1day
So, in your case you can use the following.
$dt = new \DateTime('now +1 day'); //Tomorrow
$dt = new \DateTime('2016-01-01 +1 day'); //2016-01-02