First notice the line dividing the user-mode and kernel-mode parts of the Windows operating system. The boxes above the line represent user-mode processes, and the components below the line are kernel-mode operating system services.
User and kernel modes are two processor access modes, where a kernel mode refers to a mode of execution privilege that grants access to system memory and all CPU instructions.
User mode is a less privileged processor mode than kernel mode. It uses well-defined operating system application program interfaces (APIs) to request system services. A User mode process: