Using Excel, Email, and LINE to handle orders separately typically creates three categories of problems. First, version confusion occurs when both buyer and seller modify quotations or POs independently, leading to mismatches in quantity or unit price that are only discovered during shipment or invoicing, making disputes difficult to clarify. Second, process gaps emerge because confirmation information is scattered across different tools, causing steps to be missed during handovers, and making it difficult for new staff or substitutes to quickly take over. Third, knowledge loss happens when experienced sales staff leave the company, taking with them valuable knowledge about customer preferences, historical negotiation records, and special terms that are difficult to reconstruct from available data. The solution is to centralize inquiry, quotation, PO, and shipping processes in a single system that maintains version control, tracks modifications with audit trails, and preserves historical data. Combine this with standardized operating procedures (SOP) to ensure business processes no longer depend on specific individuals.