You can install the operating system on any of the hard disk drives (HDDs) installed in the server.
NVMe drives are not supported for servers running the Windows Server operating system. If your server is equipped with NVMe drives, you have to install either the Oracle Solaris or Oracle Linux operating system to use them.
For servers equipped with Fibre Channel PCIe host bus adapters (HBAs), you can choose to install the operating system to an external fibre channel storage device.