A website is only publicly accessible as long as it is being served on an Internet-connected web server. To "delete" a website, you would just remove it from the web server. Some platforms even have deployment/undeployment options that allow you to put websites online and take them offline without actually removing the files from your web server (Tomcat and Java EE would be an example of this, although I don't think Apache, an extremely common web server, offers that and relies on removing the files from the folder serving websites).
Domains are registered on a yearly basis; if you let it expire, it will no longer point to your content.
Taking down the content is possible at any time also.
A standard website is just a collection of files, and usually you have direct access to them.
However: web sites are cached, for instance by google or archive.org.
So don't expect it to be completely gone without a trace after you removed it.
When you create a website, you have the rights to it and can delete it whenever you want. That is not to say that it won't be saved somewhere, but with storage nad domain names costing money, it would be kind of ridiculous for someone to want to pay for storing a website that is deleted. If whoever is hosting the website usees it for something without your permission, they are violating copyright laws and you have legal recourse.
Website will stay as long as you pay for your web host provider.
you can delete it yes, or sell it
Or does it stay on the Internet forever?
