By using variables you can avoid having to include sensitive information in your code, upload them to version control and so on where they could be more easily accessed.
A variable can be anything from a configuration setting, encryption key, external resource addresses, user credentials etc which you can in turn referenced in your script or application by using the variable name. When your script/app is running it will take the variable name and search your variables for the corresponding value which is only stored on your environment node(s).
You can add your variables to any node you prefer and the changes will automatically be applied to all nodes of the same type.
Learn more about how to use the feature in our documentation.