You can use the storage assigned to an ESXi host as either a Virtual Machine File System (VMFS) datastore or a raw device mapping (RDM). RDMs are not supported on the NVMe over Fibre Channel protocol.
All 6.x and 7. x versions of ESXi support VMFS versions 5 and 6.
Make sure the volumes mapped to the ESXi host have been discovered properly.
For instructions on creating VMFS datastores using either the vSphere Client or the vSphere Web Client, see the VMware pubs webpage (https://www.vmware.com/support/pubs/) for documentation on this topic.