Is it possible to link preexisting issues to new issues? And if possible, how would I do it?
The link feature is there for that, you can link issues with different reasons "duplicate" "relates to" etc...
https://confluence.atlassian.com/jiracore/linking-issues-933083070.html
Was there a deeper explanation to your questioning?
It looks like you're new here. Sign in or register to get started.