My guess is that you are on JIRA Cloud. The add-on is not available for Cloud.
If my guess is wrong and you're on Server, then yes, you can install it from the marketplace from inside the "find new add-ons" under admin. Or, if your server can't reach the internet, download it to your machine and use "upload add-on" to upload the jar.
This approach requires you to have the JIRA administrative rights. The main aim of this article is to help you achieve an organized, easy-to-maintain workflows in your JIRA instance thereby, reducin...
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