Master variables can be set once and used across all Process Definitions.  

For example, if customerID is used in every definition, instead of defining the variable for each one, customerID can be set using the master variable screen. Once the variable is defined through the master variables, each new definition will automatically include the “customerID” variable. 

Take a look at the simple master variable UI, designed to make defining variables easier and more manageable. 

You can add "variables and globals" by providing their names and selecting a data type. You can remove variables and globals by choosing them from the list. The variables and globals have default values based on their data type. The Process Instances page allows you to add and delete variables and globals.

• Variables and globals have '0' for the 'Number' data type
• Variables and globals have ' ' for the 'String' data type
• Variables and globals have 'Current date and time' for the 'Date' data type
• Variables and globals have 'false' for the 'Boolean' data type

In this example below, a list of master variables is defined to be included in each new process definition created henceforth.  

Let's create a new process definition in the example below. 

The process definition is created and displayed on the designer canvas. 

Select the Actions - Define Variables menu to view the “global variables” included in this definition.