person-demo.php

<?php

class Person
{
  private $firstName;
  private $lastName;
  private $age;
  
  public function __construct(string $firstName, string $lastName, int $age)
  {
    $this->firstName = $firstName;
    $this->lastName = $lastName;
    $this->age = $age;
  }
  
  public function getFullName(): string
  {
    return "{$this->firstName} {$this->lastName}";
  }
  
  public function describe(): string
  {
    return "Hello {$this->getFullName()}, this is your age: {$this->age}";
  }
}

$person = new Person('Jan Joshua', 'Esmer', 25);
echo $person->describe();