Customer Invoice Functions
The Customer Invoice function is used for two purposes:
• You can view and modify invoices and credit notes created by Invoice Post and Print (7.13.4). Most of the information on these sales-related invoices defaults from the associated sales order and is set during invoice post; you can modify only a small subset of fields.
• You can directly create invoices for miscellaneous customer charges or credit notes. For this type of manual invoice, you must specify most of the fields that are automatically populated during invoice post.
Sources of Customer Invoice