GetProcessTimes

[DllImport("Kernel32.dll")][return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetProcessTimes(
   IntPtr hProcess,
   out FILETIME lpCreationTime,
   out FILETIME lpExitTime,
   out FILETIME lpKernelTime,
   out FILETIME lpUserTime
);

Microsoft documentation: Link