In terms of virtualisation folks here recommended proxmox, I haven't tried it so far, but maybe it's something for you.
Reading the comments the title is a bit misleading as the conversation appears to be more storage based. I'm assuming this is a lab / testing machine that you have, so I why step into the real world and use ESXi ? The world runs on VMware. If you want a true hypervisor then I would recommend going with VMware. The workstation vm product are nice if its running on your daily driver, I use workstation Pro, but I think VMware player is still free, also people mentioned virtual box which is a good product as well.
I've used VirtualBox, run VMware Workstation on a workstation and kvm on my Laptop. Also, I work in an Esxi environment.
If you're looking for a free enterprise level virtualization solution I have been very impressed with proxmox. It let's you make both containers and VM. It has a Web interface for management. It's very esxi-y.
Think type one hypervisor here.
However, if you just want to virtualization a Linux machine to learn about Linux and mess around with virtualization check out virtual box or VMware player. Think your type two hypervisors.
Good luck!