...
The list of invoices includes all the invoices available in the system. If you don't see a specific document, rearrange the list by date or document number or use the Search field to locate the document by a string in its description, company name, or contract number. You can change the list display settings to suit your particular needs. To learn more about the list display settings, see Working with the item list.
Invoices can be based on documents of the following types: Lead, Quotation, Customer Order, or Proforma Invoice from the Sales module.
...