You must have the Jira System Administrators global permission to install Teamworkx Issue Picker for Jira.
Installing apps directly from the administration console
In Jira Cloud terms, you buy an app by subscribing to it.
To find and try Teamworkx Issue Picker for Jira app:
Select Jira settings > Apps.
Click Find new apps.
Search for Teamworkx Issue Picker.
To try or subscribe to the app, click Free trial next to it.
If you don't terminate the trial within the trial period, a subscription for the app kicks in. Trials last for a month from the start of your next billing date. After starting a trial, you can stop it from the app administration page.
Although you can re-enable the trial within the original trial period, you can't try it again beyond the original trial period. At that point, you can only subscribe to the app from the Manage apps page.
Cancel an app subscription
To end a subscription for an app, click Unsubscribe next to the app in the "Manage apps" page. Canceling an app takes effect immediately, although some apps may retain functionality even after the license period ends. If you'd like to completely stop an app from appearing in the interface, you can uninstall it.