Before we delve into invoice creation, we're first going to explain the two basic types of invoices that can be created using Introbills. The two basic types of invoices that can be created are advance payment invoices and regular invoices. Advance payment invoices are sent when you're requiring your clients to send you an advance for the work that you're doing or for the services that you're offering. Advance payment invoice is generated for a particular client and can later be subtracted from the total amount when creating the final invoice (standard invoice). In this demonstration we'll first going to create an advance payment invoice, followed by an actual invoice from which we'll subtract the value of of the advance.