Before you create a BOM, you need to check if the material type of the header material is allowed in the BOM usage. The material type defines the attributes and functions of a material, such as whether it is a finished product, a raw material, or a trading good. The BOM usage defines the purpose and application of a BOM, such as production, engineering, or sales. Only certain combinations of material types and BOM usages are valid in SAP S/4HANA. For example, you cannot create a production BOM for a material type that is not relevant for production planning. Reference: [SAP S/4HANA Production Planning and Manufacturing Certification Guide], page 63; [SAP Help Portal: Material Type].