The above categories of supporting documents are assigned to each purchase receipt in the EKKO head data table as an attribute (field: EKKO_BSTYP). This means that the class of documents allows us to distinguish delivery plans from other contracts. But how to distinguish value contracts from volume contracts? This is where the type of evidence described above begins: in the standard is the type of proof “MK” for volume contracts and “WK” for value contracts. However, both types of records have the same class of “K” records. While document categories are primarily used for categorization, document types are often used to customize them, i.e. assign attributes to document types that are then used to organize/control processes in a system. You can also find them in the EKKO table, the field name is EKKO_BSART.