There are many classes of information in any given web application so its important to understand what qualifies as a workflow variable. In Joget, workflow variables typically represent data elements that needs to be represented across the entire process as a whole. They are generally used to aid conditions and decisions within your process and aren't specific to any single activity. Take our example for instance: the requestor would probably fill out a bunch of information when applying for leave (date of application, duration of leave, reasons, etc). While those are data that needs to be stored, they aren't necessarily workflow variables since they apply only to that one form and don't really aid in determining the flow of information for our process.
On the other hand, when the supervisor decides to accept/reject a leave application, it will change the course of process flow causing activities to be launch and decisions to be activated. This in our example, the variable "supervisorApproval" needs to be a workflow variable. To create a workflow variable:
1. Right click on your process an the process tree on the left and select Properties
2. Once the window pops, click on the Create New Element icon under the workflow variables tab
3. Create a new workflow variable called supervisorApproval
Your entire workflow variable list will be displayed in the properties window. Double clicking on an item will allow you to modify it.