Variables are a very useful feature to make global changes across all your reports, or to leverage off the Variable Overrides feature in Automators

You can create an unlimited number of Custom Variables that can be used in any field that sports a red Variable pull-down button on the left of the field:

A good way of using variables is to plan ahead and think of what pieces of text may be subject to frequent change, or text that is commonly included in many different reports

This gives customers a central facility for making changes without tediously changing each Report or Text definition

There are also built-in variables for specifying dates and times, which are dynamically calculated during the execution of the Automator :