“Description” gives you details about the Issue.It's important to write descriptions so that other users can follow how the task has been handled. For example, if this issue concerns bugs in developing software, writing about how the bugs occurred in the description will allow bugs to be resolved faster. Similarly, if this is a customer support issue, the support staff will use the description to explain the questions asked by the customers.
You can format text within the description. To edit it after creating an Issue, press the "Edit" icon.
If you would like to quote the description body in a comment on the containing ticket, click the "Quote" icon in the description box. Then, the description will appear inside the comment box.