Encapsulation is used to hide the values or state of a structured data object inside a class, preventing unauthorized parties' direct access to them. It is a concept that motivates us to think through a method/class responsibility and hide its internal implementation/details accordingly. This will make it easy to modify the internal code in a long run without affecting other part of the system. Visibility is the mechanism for encapsulation.

Example for Encapsulation

<?php
class Person {
    private $name;

    public function setName($name) {
        $this->name = $name;
    }

    public function getName($name) {
        return $this->name;
    }
}

$robin = new Person();
$robin->setName("Shivani");
$robin->getName();
?>

In this simple class above. Field $name is encapsulated (private). Users of the class is not aware how $name is stored in Person class. Right now the $name is stored in memory. We can modify internal code of Person class to store it to a flat file or event a database. Users of the class will not need to change any code, in fact they do not even know how $name is stored, because that is encapsulated and hided from them.