This article presents the results of an internship conducted at the Investment and One-Stop Integrated Services Office (DPMPTSP) of Serang City, with a focus on the General Affairs and Personnel Sub-division (Subbagian Umum dan Kepegawaian/Umpeg). The study analyzes the workflow of incoming letter management within the administrative system of a public sector institution, examining the procedural stages of receiving, sorting, recording, classifying, distributing, and archiving official correspondence. A qualitative descriptive method was employed, combining participatory observation, interviews, literature review, and document analysis. The intern was directly involved in operating the Srikandi digital correspondence application, preparing disposition forms, distributing letters to relevant work units, and maintaining administrative records. The findings demonstrate that the incoming letter management process at DPMPTSP Serang City follows a structured and sequential workflow that is critical to the efficiency of internal communication and public service delivery. However, several constraints were identified, including the partial reliance on manual archiving practices, the risk of data duplication or loss, and the limited capacity of staff in digital documentation systems. These findings suggest a need for comprehensive digital transformation in correspondence management, supported by regular staff training and updated standard operating procedures, to strengthen administrative effectiveness and service quality at DPMPTSP Serang City.