Purchasing, procurement, and strategic sourcing are interconnected yet different activities within supply chain management. Purchasing refers to the transactional aspect of buying goods and services, often focused on cost and availability. It typically involves processing orders, approving requisitions, and managing supplier catalogs $($Guttman et al$.,2024).$ Procurement, on the other hand, is a broader, tactical activity encompassing the entire process of acquiring goods and services, from requisition to payment, under existing contracts $($Guttman et al$.,2024).$ It ensures that the purchasing process aligns with organizational policies and supplier agreements. Strategic sourcing is a more strategic and analytical approach, focusing on supplier selection, contract negotiation, and long$-$term supplier relationships to achieve cost savings and supplier performance improvements $($Guttman et al$.,2024).$ These three elements work together to optimize the supply chain: purchasing focuses on transactions, procurement on policy and execution, and strategic sourcing on long$-$term efficiency and supplier management.

The use of e$-$commerce in procurement offers significant advantages and some disadvantages. E$-$commerce enables companies to automate procurement activities, streamlining processes such as requisitioning, supplier catalogs, and invoicing $($Guttman et al$.,2024).$ This can result in reduced transaction times and improved accuracy in orders and payments. Additionally, it enhances visibility into spend data, allowing for better strategic decisions. However, e$-$commerce systems can be expensive to implement and maintain, requiring significant investments in technology infrastructure and employee training $($Guttman et al$.,2024).$ There may also be security concerns related to sensitive supplier and transactional data.

Capacity planning focuses on determining the production capacity needed to meet demand, ensuring resources like machinery, labor, and raw materials are available to meet production goals $($Heizer et al$.,2020).$ Materials planning, in contrast, involves determining what materials are needed and when, ensuring that they are available in time for production. Push$-$based production strategies involve producing goods based on forecasts, leading to higher inventory levels and potential overstock, while pull$-$based production is driven by actual customer demand, minimizing inventory but requiring a more responsive supply chain $($Heizer et al$.,2020).$