Import ISO option that allows ISO images to be uploaded.Import ISO option is removed from the interface.VMware vCenter Server 9.x
The removal of the Import ISO option is by design.
Starting with vCenter Server 9.0, Lifecycle Manager no longer supports importing ISO files.
The following file types are supported for import in vCenter Server 9.0 and later:
Offline bundles imported into the vSphere Lifecycle Manager depot
JSON image files imported into the Image Library, a cluster managed by Lifecycle Manager, or a standalone ESXi host
For more information, refer to: Working with Image Library