When an action is chosen from the Task Builder's Available Actions pane and its properties entered, a general description and other information about that action is automatically generated and displayed in the Steps pane. All available actions include a Description tab within its properties allowing you to fully customize the description of any step when it appears in the Steps pane.
Go to the properties of the action/step and select the Description tab.
Enable the parameter labeled Use custom step description and type the desired description (as illustrated below):
This description will display in the Steps pane in place of the default description (as shown below highlighted in blue):
Adding Task Steps