You can directly access the EndTimeStamp() of a Task or Case and format it for your needs. The code that is actually displaying these values in the designer workflow is written in JSP. You can inspect and adapt them for your needs in `[designer-dir]/webapps/ivy/wf`. See `taskdetails_panel.jsp` and `casedetails_panel.jsp`
In script steps you can directly access them:
ivy.task.getEndTimestamp();
ivy.case.getEndTimestamp();
So typically you would first write a query to get all tasks/cases that you want to show to the user. And afterwards use the EndTimestamp values and show it on the ui.ui.
![alt text][1]
[1]: https://answers.axonivy.com/upfiles/taskDetails_panelJsp_taskRuntime.png