Mainly there are two types of variables: action parameters and environment variables.

An action's parameters are stored with the action and are the same for all calls to that action. If you change the action parameters defined for an action, and then view the action properties for a call to that same action in a different part of the test, you can see the action parameters have changed. However, the actual values specified for input action parameters and the locations specified for action output parameters can be different for each call to the action. When you insert a call to a copy of an action, the copy of the action is inserted with the action parameters and action call parameter values that were defined for the action you copied. When you split an action, the action parameters are copied to both actions. The action call values for the second action are taken from the default values of that action's parameters.

Environment variables can be accessed from your test. Throughout the test run, the value of an environment variable remains the same, regardless of the number of iterations, unless you change the value of the variable programmatically in your script.