Document Types 
Definition
A key that is used to classify accounting documents and distinguish between business transactions to be posted. The document type is entered in the document header and applies to the whole document.
Use
The document type has the following functions:
Differentiating between business transactions. The document type tells you instantly what sort of business transaction is in question. This is useful, for example, when displaying line items for an account.
Controlling the posting to account types (vendor, customer, or G/L accounts). The document type determines which account types that particular document can be posted to.
Assigning document numbers. A number range is assigned to every document type. The numbers for the documents you create are taken from this number range. The original documents from one number range should be stored together. In this way, the document type controls document storage.
For more information, see Document Number Assignment and Controlling Document Storage Using the Document Type
Applying the vendor net procedure. This means that any discount and the net amount are calculated (and posted) when the vendor invoice is posted.
The following figure illustrates the significance of the document type:
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Document types are defined at client level. The standard system already contains document types which you can use or change. Before deleting document types, check whether they are currently used in the system.
Note
The system usually defaults the appropriate document type when a business transaction is entered. With some transactions (such as clearing transactions), you define document types that are required for automatic postings yourself.