Complexity seems to be a custom field that one of your admins added. At least I have never seen this field in any default project. Assuming you are an admin - go to Jira settings > issues > custom fields and find the Complexity field. The the far right click on the ellipses and choose configure. You should see your options there and you can edit them. Note that this will change for any project using this field.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.