Object-Oriented Programming (OOP) is a programming paradigm that utilizes objects, which are instances of classes, to structure and organize code. It provides a way to model real-world entities and relationships between them.

PHP is a popular programming language for web development and also supports OOP. In PHP, classes are used to define blueprints for creating objects, and objects are created using the `new` keyword.

Here’s an example of a simple class in PHP:

class Person {
// properties
public $name;
public $age;

// constructor
public function __construct($name, $age) {
$this->name = $name;
$this->age = $age;

// method
public function sayHello() {
echo “Hello, my name is ” . $this->name . ” and I am ” . $this->age . ” years old.”;

In the example above, the `Person` class has two properties (`name` and `age`), a constructor method (`__construct()`), and a method (`sayHello()`). The constructor method is called when an object is created and is used to initialize its properties. The `sayHello()` method can be called on an object to display a greeting message.

To create an object of the `Person` class and call its methods, you can do the following:

$person = new Person(“John”, 30);
$person->sayHello(); // Output: Hello, my name is John and I am 30 years old.

In addition to properties and methods, PHP classes can also have other features such as inheritance, encapsulation, and polymorphism.

Inheritance allows a class to inherit properties and methods from another class, creating a parent-child relationship. Encapsulation refers to the practice of hiding internal implementation details and providing a clean public interface. Polymorphism allows objects to be treated as instances of their own class or their parent classes.

Overall, OOP in PHP provides a way to create modular, reusable, and maintainable code by organizing related functionality into classes and objects. It allows for better code structure and easier code maintenance, especially for larger projects.