Export virtual machines to a virtual appliance (ISO) or a cloud service. More information: https://www.virtualbox.org/manual/ch08.html#vboxmanage-export.
VBoxManage export --output path/to/filename.ova
VBoxManage export --legacy09
VBoxManage export --ovf09|ovf10|ovf20
VBoxManage export --manifest
VBoxManage export --description "vm_description"