Text Processing 
You can incorporate various texts into the output of a billing document, in order to provide additional information. For example, you can insert item texts from an order into an invoice, or include marketing information dependent on the bill-to party. You can also incorporate texts that are required by law or texts that fulfill specific company regulations.
Prerequisites
You have set up text processing as described in Customizing for
Customer Relationship Management under 
Billing
Services Define Settings for
Text Processing 
.
Features
Text Definition
You use SAPscript to define the texts that you want to include in your billing documents.
Text Determination
You define text determination procedures to control the assignment of texts to a billing document header or item. Text determination procedures control the following:
Which texts are mandatory or optional
How texts are called up
The sequence in which they should be displayed within text objects in billing
Example
You can define that each billing document item must have a mandatory text. This text should be copied from the item description, or, if no item description is available, from the product description.