PHP - Understanding Mvc Sorting System

<?php

if(isset($_POST['submit'])){

    $name = $_POST['name'];
    $email = $_POST['email'];
    $password = $_POST['password'];
    //$pass_hash = PassHash::hash($_POST['password']);
    $hash = password_hash($password, PASSWORD_BCRYPT);
    
    $stmt = $pdo->prepare("INSERT INTO hash_test(name, email, password) VALUES(:name, :email, :password)");
    $stmt->execute(array(
    ':name' => $name,
    ':email' => $email,
    ':password' => $hash
    ));
    
    if ($stmt->rowCount() ==1){
        echo "Registration Successful";
    }else{
        echo "There was a problem taking your request";
    }
}
?>

 
<?php

if(isset($_POST['login'])){
    
$password = $_POST['password'];

$stmt = $pdo->prepare("SELECT email, password FROM hash_test WHERE email=:email AND password=:password");
$stmt->execute(array(
':email' => $_POST['email'],
':password' =>$password
));

//if ($stmt->rowCount() ==1){
if (password_verify($password, $hash)) {
        /* Valid */
        echo "Right";
    } else {
        /* Invalid */
        echo "wrong";
    }
//}
}

?>
 

class Greeting {

  // the __construct didn't do what I originally wanted. Denfine the hour outside the method (I don't know why this is a good/bad idea)
  /*
  public function __construct()
  {
    $hour_of_day = date('G');
  }
  */
  
  public function callGreetingPhrase()
  {
      return $this->getGreetingPhrase();
  }

  // the setter doesn't seem to have a purpose here. I tried using it so that I could pass in a value of my choosing (for testing purposes) can't get it to work though
  /*
  public function setGreetingPhrase($value)
  {
      $this->hour_of_day = $value;
  }
  */
  
  private function getGreetingPhrase()
  {  
	  $hour_of_day = date('G');
	  
	  if($hour_of_day < 12 ) { // if it's before 12pm
		
		$greeting_phrase = "good morning";
		
	  } elseif($hour_of_day >= 12 && $hour_of_day < 18 ) { // if it's after 12pm but before 6pm
		  
		$greeting_phrase = "good afternoon";
		  
	  } else { // what is left over - after 6pm until midnight
		
		$greeting_phrase = "good evening";
		
	  }

	  return $greeting_phrase;
  }
  
}


$greeting = new Greeting;

echo $greeting->callGreetingPhrase();

can you guys help with this a little bit?  i've been in so many companies.  I get so sick of this.  people throw terms around all the time and a lot of times, at least what I've noticed, is that a lot of people don't even really know what they're talking about.  take for instance, this:

https://www.php.net/manual/en/class.iterator.php

if you consider the link, it is calling the iterator a class.  but, in the article it is described as an interface.  to me, that's just ridiculous.  you see, what's going to happen with that, is that I'm going to go into a meeting next week and some person from india is going to argue with me about ""well, no, a class is not an interface.....yada yada..."", and on and on and on.  obviously this is extremely simple, and most CEOs understand that.  I've never understood why engineers do not.  it's nothing more than a hierarchy.  everything is.  sooooo.....to start here, does anyone reading this understand what I'm trying to say?  This is nothing more than information management, as everything is anyway.  That's why it's very simple.  at this point, I would think that no one should have to write code anymore, even if the concepts of low code and no code did not exist.  code is so patternized anyway, and there are only so many objects on Earth to mimic in the electronic world, is that not why frameworks were created in the first place?  let us start there.  comments anyone?  thanks.

Adam