All Cowbee virtual machines (VM) are embedded into 2 data format, namely, OVA and OVF which are Open Virtualization Format (https://en.wikipedia.org/wiki/Open_Virtualization_Format); once VM image downloaded, you shall play them under any virtualization platform (AWS, Alibaba, Azure, Google Cloud, Tencent Cloud, Qemu\KVM), by default you can directly play with below application,
1) VMware Workstation Playe (https://www.vmware.com/products/workstation-player.html)
2) VMware Workstation Pro (https://www.vmware.com/products/workstation-pro.html)
3) VMware vSphere (https://www.vmware.com/products/vsphere.html)
However, it is not limited and convert to other data format,
1) OVFtool (https://code.vmware.com/web/tool/4.4.0/ovf)
2) Qemu-tool (https://www.qemu.org/docs/master/tools/index.html)
Yet, there are other softwares on market that compatible to conduct the VM conversion task. It is highly recommend you to test the best for you purpose. Good luck!