Direct Billing 
You can use direct billing to immediately create a billing document for a transaction or delivery that you are processing. In the export business, for example, you might need to provide an invoice with the goods that are shipped.
With direct billing, billing documents are automatically created when the following takes place:
The transaction is saved (in the case of transaction-related billing)
Goods issue is posted (in the case of delivery-related billing)
In a sales transaction, you choose Billing as a follow-up transaction
You have activated direct billing for each business partner for which you want to use this procedure. You do this in the CRM WebClient UI, on the Accounts page in the assignment block Sales Area Data.