In standard customizing setting for defining billing date which is applied in billing document is basically proposed based on date of actual GI (goods issue) happened. But standard SAP provide a basic requirement for your customer probably if the want to settle every billing document in end of the month.
The required setting is done first in customer master. But please be remembered, that a customer has some perspective view that is defined as partner function: sold-to party, ship-to party, bill-to party, payer, and so on. Partner function payer will determine the defined date in the billing document.
Here, for the testing purpose, I used customer 1000, which is have partner function 1050 as payer.
Then the appropriate customizing I did in payer master data. Change customer master data in t-code XD02. Enter the appropriate values: company code data and sales area data.
In Sales Area Data, in tab Billing Documents, in field Invoicing dates, enter AM: Agreement Monthly. This value means that billing document will be created automatically for every end of month.
The effect in sales order document is in tab Billing Document in item data, the value in Billing Date is set to end of month of July, 31 2013.
As we seen in partner data in line item, the partner function payer will determine the proposed value for this billing date. Since I maintained the invoicing date for this payer as “AM” thus, in sales order that used this payer the billing date will set automatically to end of the month, that is 31 July 2013.
Even thought the actual GI date is posted on 09 July 2013. This date will not influence the billing date in billing document create later.
When creating billing document, I do not filled up the field Billing Date means it leaves blank. Only enter the delivery document then pressed enter.
Go to header data of billing document, then you will find the field Billing Date, thus you can change your billing date here.