The feature allows to create CRM Contact right from issue and set this contact as reporter automatically.
'Create Reporter' function is in 'More' menu of issue. It is accessible for users who:
Have permission to edit issue,
Have permission to add contacts to CRM Directory,
Have permission to create JIRA users
After that empty CRM Contact Card opens:
Fill it with needed information and press 'Save'. New contact will be added to CRM Contacts Directory, new JIRA-user will be created and this new user will appear as reporter of the issue.