How to edit Affects Version and Fix Version fields?

Problem

I can't edit the Affects Version/s and Fix Version/s fields on my Jira issue, though I created Versions in my Jira project.

Solution

Those two fields must be configured on the screen:

https://community.atlassian.com/t5/Jira-questions/Affects-Version-s-built-in-field-non-editable/qaq-p/88987