In SAP S/4HANA, the user types that can log on in interactive mode are Dialog User and Service User. Dialog Users are designed for human interaction, allowing individuals to log on via the SAP GUI or Fiori launchpad to perform tasks like data entry or reporting. They support full interactive access, including personalized sessions and user-specific settings. Service Users, while primarily used for web-based or anonymous access (e.g., via Fiori apps or web services), can also support limited interactive logon in specific scenarios, such as testing or administrative tasks, depending on system configuration. System Users are intended for background processes, like batch jobs, and do not support interactive logon. Communication Users are used for machine-to-machine interactions, such as API calls, and are not configured for interactive access. These distinctions ensure that interactive access is restricted to appropriate user types, enhancing security by limiting human logon capabilities to Dialog and Service Users while aligning with SAP’s user management framework.