With CapsuleCRM for Jira you can easily add new contacts to Capsule.
Adding a Contact
If there is no contact present in your CapsuleCRM environment for the current reporter, you will see a screen prompting you to add the user to capsule.
When you click the "Add" button a new page will open in which a new contact can be created.
After adding the relevant contact details you can save the page and on a issue refresh you'll be able to see the new contact details in Jira.