Unfortunately, this isn't something that JIRA Cloud can do at the moment.
In the Atlassian Marketplace, there is the Confluence Cloud version as you have mentioned but not for JIRA at the moment.
We've been tracking a similar request here JRACLOUD-10465 but it was closed as we do not have any plans to implement the feature.
There are other specific request in the tracker which are still open which might interests you:
Alternatively, you may find it easier, or be more likely to guarentee success if you engage an Atlassian Partner.
Hope this helps,
We have just released an electronic signature plugin for JIRA Cloud. Would appreciate your feedback on it if you are still looking.
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event