What is Customer' Voice for Jira
Customer' Voice lets your customers vote for your Jira issues without consuming a license.
For this you need two projects. One that contains the issues your customers should vote for and the second one has to be a service desk project.
How to Use
Create a JQL that returns the issues you want your customers to vote for (e.g. project = "VOICE" and resolution is EMPTY).
Open your Service Desk project, select Queues => Customers' Voice, insert the JQL and click Save
Go to the portal for this service desk. Here you (and also your customers) can vote for these issues.