Creating a Sub-task by Splitting Parent's Issue in JIRA in Testing

Sub-task issues are those issues that originated from another issue (the parent issue) by splitting it up into several smaller child tasks which can be assigned and tracked separately. Splitting issues into smaller tasks usually provides a good visual of the progress on the issue, and allows each person involved in resolving the issue to understand what part of the whole issue they are responsible for.

All the sub-tasks which are related to the parent issue are summarized (information about each task) on the parent issue's main screen. Sub-tasks always belong to the same project as their parent issue. Sub-tasks have all the same fields as standard issues, e.g. Summary, Reporter, Description, Assignee, Status. Each sub-task has a different set of issue types from their standard issue types.

A sub-task cannot have his own sub-task. In order to do so you have to first convert the sub-task into a standard issue. You would then be able to create sub-tasks for it; in other words we can say that, only standard issues are able to create sub-tasks.

To create sub-tasks, you should have the permission (to create a sub-task) on the parent issue's project. Note that you will able to create sub-tasks only if your JIRA administrator has enabled sub-tasks and added the sub-task issue type to the project's issue type scheme.

How to create a sub-task:

1. Click on the issue which you would like to be the parent issue of the sub-task you are about to create. The particular issue will open.
2. Click on the "More Actions" drop-down and select the "Create Sub-Task" link. The "Create sub-task"  window will appear.
   
   
   
   
3. Fill in all the details as needed, and then click on the "Create" button at the bottom of the window.