Summary

There are cases where customers don't enable the 'Epic link' field in the create/edit issue screens as users will be able to see wide list of EPICS from all the projects.

On Kanban boards, assign issues from the backlog to an Epics is quite easy, it's just about dragging the issue from the backlog to the Epic panel. However, if the issue is not in the 'Backlog' and is already transitioned "In-Progress" status, then it becomes tricky since the board doesn't show the issues in 'In-Progress' status and editing issues for 'Epic link' field is not an option since the field is not enabled in create/edit issue screens.

Issues inside an Epic are shown under 'Issues in Epic' section, but it doesn't have an option to add issues as per design. So there is a need to go with some board related hacks to overcome these type of scenarios.
One of the use-case scenarios is explained in this article below with examples and solution. Consider a scenario mentioned below where users are blocked:

• The users forgot to map the issues to EPIC in the beginning before making transition to 'In-Progress' or 'Subsequent (Testing, Done etc)' statuses.
• As part of the Kanban board design, it allows only issues in the 'To Do' category to be available on the backlog. Hence only issues in 'To Do' category will be available in backlog.

Environment

Jira 8.X and 9.X versions.

Solution

• For the Kanban boards to display backlogs, we need to first enable 'Kanban Backlog' for the boards by following this article Configuring columns - Enabling Kanban Backlog. 
  This should be done by adding a specific status called 'Backlog' to the board configurations. It enables, the Kanban backlog option including EPICS, Versions panel for the board.
  
  
• Once Kanban Backlog is enabled, users should be able to see the 'Backlog' for the board having issues with statuses mapped for 'Backlog & To Do' categories. These issues can be easily dragged and dropped under 'Epics' to have direct mapping. However issues in the 'In Progress' category will not appear in the backlog and hence it becomes tricky to map these issues to the epics. Here are the steps to handle such scenarios.
  
  
• We enabled Kanban Backlog by adding a specific status called 'Backlog' to the board configurations. Now, we could see the issues 'Backlog' and 'To Do' status are now available in the backlog view.
  In our validation example: issues with keys VIV-3, VIV-6, VIV-7'and VIV-8 are qualified to be part of the backlog view based on default configs.
  
  
  

• At this stage, edit the board configurations temporarily to map the 'In Progress' Status to 'Kanban Backlog' category as shown in the screenshot.
  This setting enables the issues in 'In Progress' status also available as part of the backlog view.
  
  
  
  

• In our validation example: Issues with keys 'VIV-4' and 'VIV-5' are mapped to 'In Progress' Status. Now you can map the issues in the 'In Progress' status to the EPICS using drag and drop option. Once done You could see EPIC information (Testing EPICS - highlighted in orange colour) is now reflected on the issues as per second screenshot. 
   
  
  
  
  

• Once the issues are mapped with EPICS as per requirement, restore board settings like before by moving 'In Progress' status to 'In Progress' category (column).

• These set of actions will help map issue in 'In Progress' status to the epics like other issues in backlog and once the activity is complete all issues with 'In Progress' status will appear under same category/column as before in Board views.