Autoinvoice is the invoice which is automatically created on the basis of Purchase order number or receipt number. For that we have to first create Purchase order & receipt in PO module and then after submitting the report 'Pay on Receipt Autoinvoice' from AP module invoice gets created automatically.
Partly right. Autoinvoice is the process of creating an invoice in Accounts Receivables Module. This customer invoice can be raised against a Sales Order or from Project Accounting.
Auto Invoices are also used in Service Contracts as a concurrent Program namely "Auto Invoice Import Program". This program is Owned by Oracle Receivables. It imports the billing transactions from the "Service Contracts Main Billing" Program (This Program Belongs to Oracle Service Contracts) into Oracle Receivables & generate the invoice details. You have to pass down certain parameters regarding the Service Contract while running this program. Also this Program pass down the information regarding Invoice No. & Taxation from Oracle Receivables to update the Contracts Billing History when "Service Contracts Fetch Receivables Info for Billing" Concurrent Program (This Program also belongs to Oracle Service Contracts) is run.