SAP MM (Materials Management) is a module within the SAP ERP (Enterprise Resource Planning) system that deals with the management of procurement and inventory functions of a company. It includes features such as material procurement, inventory management, valuation, and vendor management. With SAP MM, a company can manage the procurement process, including purchase orders, request for quotations, and supplier selection. It also allows for the management of the entire inventory cycle, from the receipt of goods to the issue of materials for production.