Which function is NOT typically part of service purchasing in SAP S/4HANA?

Inventory categorization is not typically part of service purchasing in SAP S/4HANA because service purchasing focuses on procuring services rather than physical goods. In service purchasing, activities center around managing service agreements, overseeing performance, and ensuring that services are delivered as per contracts.

Service entry sheet creation is crucial as it allows users to document and approve the services rendered. Price negotiation is important to agree on terms and conditions that benefit both the buyer and the service provider. Quality control monitoring is also relevant, as it ensures that the services meet the required standards and specifications set forth in the contract. Therefore, inventory categorization, which relates to how physical goods are classified and managed in a warehouse or inventory system, does not align with the nature of service purchasing.