Setting the default timezone (otherwise, everything will be UTC)

date_default_timezone_set('America/New_York');

Creating a NOW timestamp as Object

$today=new DateTime();
echo $today->format('Y-m-d H:i:s');

Creating a NOW timestamp procedurally

$today = date_create();
echo date_format($today, 'Y-m-d H:i:s');

Time between two dates (not the cleanest way)

$this_date = (new DateTime()) -> getTimestamp();  //today
$other_date = strtotime('2020-07-14'); //some other date

//Result is in number of seconds, will need to be converted
$delta = $that_date-$this_date;

Quick code for time between two dates:

date_default_timezone_set('America/New_York');
	
$date_format='F jS, Y';
	
$this_date = (new DateTime()) -> getTimestamp();  //today 
$that_date = strtotime("2020-07-07");  //random date mySQL format

$delta = $that_date-$this_date;
$delta = round($delta/60/60/24,1);

$that_date = date($date_format,$that_date);

if ($delta > 0) {
		$result="
		<p>
		$that_date is $delta day(s) from today
		</p>
		" ;
		
	echo $result;
    } else {
	$result="
		<p>
		$that_date was $delta day(s) ago
		</p>
		" ;
	echo $result;;
	
}