Note that this information applies to invoice queues (more information). A different type of queues is available for documents in general, compound documents, or batches (more information).
When you want to divide the verifying and optimizing work among multiple workstations, one way is to use queues.
Assume you want certain Invoice Verify operators to process invoices from certain suppliers. After each invoice is scanned or imported, you can add it to a queue according to the supplier. Invoices for supplier names starting with A through D could go into queue 1, suppliers E through G into queue 2, and so on.
The Invoice Verify operators can run jobs that process invoices from "their" queues.