Successful digitalization requires a deep understanding of the practices surrounding self-service solutions. Such understanding can be developed through direct interaction between citizens and service providers. In this study, we contribute to such understanding by exploring how explicit and tacit knowledge is exchanged during citizen-caseworker interactions. We do so by examining how citizens and caseworkers share knowledge while interacting with a digital self-service application for financial assistance. Although self-service solutions aim to improve service delivery by allowing citizens to serve themselves, we find that they can also create challenges. Citizens need to acquire relevant knowledge and skills, and public employees must often correct application errors and assist citizens during service procedures. Our findings from observations and interviews reveal that both parties hold essential knowledge for the use of self-service solutions. These interactions facilitate bidirectional knowledge-sharing, enhancing citizens’ confidence and helping caseworkers refine their guidance methods. The paper discusses how knowledge-sharing occurs when caseworkers guide and support citizens through the process of digital self-service applications and how these guidance sessions can benefit the development and design of digital self-service solutions in the public sector.