DT Invoice is an extension that integrates with DT Register providing clients with the ability to automatically generate PDF invoices containing event registrations as well as additional line items for billing. DT Invoice can also be used independent of DT Register and provides clients with a trusted billing application that allows you to email invoices to customers and receive payments against those invoices. We have put together some basic info here that should help you to know what to do with the items you just downloaded.

Read more: DT Invoice Documentation