During data input for sales documents, the system supports you by analyzing various sources of information. The aim is to make creating documents easier by using default values or fixed reference data.
Find the possible sources of information and data examples in the figure below.

Where does the data come from and how can you use it?
Master data: The system reads the master data defined for a customer, a material, or a pricing condition. For example, the specific terms of payment for a customer can be found. The sales information from a material master can serve as the source for the delivering plant.
Existing document data: Document data that has already been entered or determined automatically by the system can be used to enter additional document data. For example, the delivering plant is used - along with other information - to determine the shipping point.
Customizing: Default values for creating documents can be defined in Customizing. For example, you can set a default value for the delivery date or configure a delivery or billing block in the sales document type. You can also define strategies in Customizing for determining document information based on combinations of several criteria (for example, determining the shipping point through a combination of delivering plant, loading group, and shipping condition).
Hard-coded system control: The system uses a hard-coded control in the SAP program to put different sources of information into a sequence - for example, when proposing plants automatically.
Proposing Order Data from Master Data
The next figure illustrates what different types of master data you can enter in the SAP system. That can be information on business partners, materials, customer/material, item proposals, bills of material, prices, discounts and rebates, taxes, freight, output and texts and so on.

It is advisable to store as much data as possible in master records in the SAP system. This will save you time during order entry and help you to avoid incorrect entries. The system will frequently access this data during order processing.
In the order overview, you can create items for the ordering company by entering customer-specific material numbers.