Too bad you are unable to distinguish Tor from the Tor Browser. Perhaps you should start reading at the real page that was buried under an ugly domain site:
https://2019.www.torproject.org/If you are able to ignore the existence of the browser entirely, then we could move forward.
vpn is not meant for anonymity, the vpn server knows everything about you. Tor doesn't work this way, so called "Onion" networks work like the peels of an onion. You talk to a computer encrypted, this talks to a second computer and encrypts again the already encrypted data, this goes to a third, etc. At the opposite side the process reverses.
Once you enter the network, you don't get anyone's IP. A few of them share theirs, so you can enter, but once inside there are no IPs. Ideally you will never go out, but people are foolish enough to browse the "normal internet" from it. There are weakness at both the entry and exit, because that's outside its boundries.
The tor node you connect to, only knows your ip is connected to the onion, but has no idea what the content is.
You don't "register" a .onion. When you run your own node, you can simply host your own content securely, and it generates a random address for you, not unlike a crypto wallet address. If you don't share this address, nobody will ever know about it.
Tor nodes can be exit nodes, can be normal nodes that publish their IP to let others enter the network, and can be unpublished (only the people you tell know) or could just be bridges that relays from other tor nodes and nothing more, no in or out.
The exit node is what allow "normal" web content to be seen from tor. Don't run an exit node, leave that to the "whales" that can afford fighting half internet. Feel free to publish your ip or not depending on how free your country is, it helps people from oppressed regions easier access to the network.
You are the only one that can reveal or not your info. Also using secure software helps, avoid anything that is not Free and Open Source software, especially operating systems. And don't do stupid things.