Digital Invoicing (DI) has become an important component of digital transformation aimed at improving working capital management (WCM) in manufacturing companies. By digitalizing invoicing processes, companies can accelerate billing, improve receivables collection, and strengthen cash flow. This study analyzes and evaluates the association between DI implementation and the efficiency and effectiveness of WCM at PT XYZ, an Indonesian flour manufacturing company. Before DI implementation, the company faced liquidity constraints, with a Current Ratio (CR) of 0.81 and a Quick Ratio (QR) of 0.38 at the end of 2024. Approximately 83% of sales were conducted on credit, while the manual invoicing process required an average of 5.0 days from invoice creation to delivery. Monthly secondary financial data covering 11 months before DI implementation (February–December 2024) and 11 months during the DI implementation period (February–December 2025) were analyzed using the Shapiro–Wilk test, paired-sample t-test, and Wilcoxon signed-rank test, as appropriate. Effect sizes and 95% confidence intervals were also assessed to evaluate practical significance. The results show significant reductions in Raw Material Conversion Period (RMCP), Work-in-Process Conversion Period (WPCP), Finished Goods Conversion Period (FGCP), and Average Collection Period (ACP), indicating improvements across several WCM components. ACP decreased from 38.73 to 34.18 days (p = 0.005; r = 0.849), representing a large effect and the improvement most closely associated with DI through faster invoicing and receivables collection. RMCP decreased from 63.82 to 38.82 days (p = 0.035; d = 0.736), WPCP from 5.91 to 4.18 days (p = 0.004; d = 1.111), and FGCP from 3.91 to 3.00 days (p = 0.024; d = 0.800). PDP also decreased from 92.45 to 63.27 days (p = 0.026; d = 0.789), which may reduce cash-flow flexibility and partly offset improvements in other WCM components. CR improved significantly (p = 0.003; |d| = 1.169), while QR increased descriptively from 0.374 to 0.410 but did not improve significantly (p = 0.166; |d| = 0.451). The Cash Conversion Cycle (CCC) decreased from 19.91 to 16.91 days, but the change was not statistically significant (p = 0.638; d = 0.146). Overall, the findings indicate that DI was most closely associated with improvements in receivables collection, while broader WCM improvements were supported by complementary operational and financial practices. The absence of a significant CCC improvement demonstrates that gains in individual WCM components can be offset by changes in other components. Therefore, maximizing the benefits of DI requires integrated management of receivables, inventory, procurement, payables, and cash flow, supported by adequate cash-based liquidity buffers.