Using Class Properties:

Define properties within your class and use them to store and share data between different methods.

                 class Example {
                    private $sharedData;

                    public function setData($data) {
                        $this->sharedData = $data;
                    }

                    public function getData() {
                        return $this->sharedData;
                    }
                }

                // Example usage
                $instance = new Example();
                $instance->setData("Hello, World!");
                echo $instance->getData();