Updating a JIRA Issue from Salesforce

You can directly edit JIRA issue in Salesforce.  The edit option presents a full issue edit page in Salesforce that contains the same fields that would be editable for that issue and by that user (or the Integration User for JIRA Cloud users) in JIRA.

Clicking on the edit icon on the right column of the Related Issues table will result in the issue edit window.  The actions from this window are directly posted to the corresponding JIRA issue.