The Sales and Distribution (SD) component allows you to generate invoices from billing documents. However, if you use Accounts Receivable (FI-AR) functions for miscellaneous sales, or you do not use SD, you may need to generate invoices straight away in FI-AR. To do so, you can use the correspondence function, for which purposes you can use the sample correspondence type SAPS1 and SAPscript form F140_INT_SING_01.