With the vSphere Web Client and the vSphere Client, you can connect remotely to vCenter Server. With the vSphere Client you can also connect directly to ESXi from any Windows system.
However you cannot connect to ESXi host directly using vSphere Webclient
The vSphere Web Client and the vSphere Client are the primary interfaces for managing all aspects of the vSphere environment. They also provide console access to virtual machines.
In the vCenter Server hierarchy, a datacenter is the primary container of ESXi hosts, folders, clusters, resource pools, vSphere vApps, virtual machines, and so on.
You can create a single virtual machine and install a guest operating system and VMware Tools on it. You can clone or create a template from an existing virtual machine, or deploy OVF templates.
What determines the virtual machine hardware version?
The version of the ESXi host on which you create the virtual machine determines the virtual machine hardware version.
All virtual machines have a hardware version.
What does virtual hardware version indicates?
The hardware version indicates virtual hardware features that the virtual machine supports, such as BIOS or EFI, number of virtual slots, maximum number of CPUs, maximum memory configuration, and other hardware characteristics.
You can add virtual disks and add more space to existing disks, even when the virtual machine is running.
In the vSphere Web Client, you must select an existing customization specification. To create customization specifications, you must use the vSphere Client