Who owns the website? The owner or company that created the site?
When someone works with Open Source, they have to have a bit of legal overlap. More What Does A Copyleft License Mean? That’s how everyone knows copyright. We encounter this in paintings, photographs, texts, etc.
Copyleft “When creating a derivative work from a work that is only available under a copyleft license, that derivative work must be offered under the same (copyleft) license as the original work.” The principle of copyleft was created by Richard Stallman and applied in the copyleft licenses of the GPL and GFDL GNU project.
Well, now we move into practice.
WordPress is licensed under the GPLv2. So if someone makes you a WordPress website, then everything is yours. He cannot claim any license right. That is, if you make a website from the beginning on the WordPress system, even a paragraph in the contract that the website is the work of a contractor will not help him to keep the work.
The WordPress website is simply yours. With one exception. The graphic designer can license his appearance. But that’s the only thing.