As you can see, it is not very complicated to add a default configuration to your Drupal 8 module and to create a custom form for your configuration.

Drupal 8 provides you with powerful tools to define the form and create the required menu items, so you can focus on the form itself and give your users a good user experience.

Having to upgrade a configuration defined in previous versions, though, is not as simple. In the next chapter, we will describe how to upgrade your variables from older versions of Drupal to make them available with the new Configuration Management system.