how to add sub task estimate and it should tie with original estimate.

[srinivas]

how to add sub task estimate and it should tie with original estimate.

[Nic Brough -Adaptavist-]

Make sure the "time tracking" field is placed on the issue create screen.  You'll be able to add an estimate and adjust it later.  You may need to check that the field is valid for sub-tasks in your field configuration, and you probably want to have it on the edit screen as well.  The worklog and edit functions will handle the "tie with original estimate" for you.

Note that if you're using JIRA Software, estimates on sub-tasks are treated as separate entities to the parent issues.