This ASUG paper shows why AP modernization should start before the S/4HANA cutover. It explains how xSuite Invoice helps finance teams reduce manual work, standardize workflows, and improve process transparency while keeping the ERP core clean. The paper highlights how Clean Core principles, SAP BTP, and AI-supported automation can increase touchless processing and reduce cycle times. ASUG and xSuite also share customer examples that show measurable improvements in invoice processing and AP efficiency.