VTiger is a CRM, but also has some accounting elements such quotes, invoices & orders. Invoice functionality is as in any other accounting system – collect payments, export to PDF, mail or email it. If you are dealing with few invoices a month per customer – that might just work. However, if you end up with 10+ invoices that need to combined – we might be able to help. Currently, VTiger does not allow to combine multiple invoices into one “Master Invoice”, so we customized it to allow users to search for invoices using filters and select the ones that need to be combined and create one “Master Invoice”. We also added few custom fields to help keep track of the invoices combined. In addition, the “Master Invoice” will include all the items from the single invoices and will have a unique PDF template, which is easy to follow for the customer.