X-Pack is an Elastic Stack extension that provides security, alerting, monitoring, machine learning, pipeline management, and many other capabilities. By default, when you install Logstash, X-Pack is installed.
If you want to try all of the X-Pack features, you can start a 30-day trial. At the end of the trial period, you can purchase a subscription to keep using the full functionality of the X-Pack components. For more information, see https://www.elastic.co/subscriptions.