When you finish a project, have stopped using your blog, or closing your business, you may want to consider removing your website from WordPress. There are a few things that you can do and approaches you can take depending on your situation.

For example, a blogger who wants to end or take a break from their blog, but wants to keep the posts available through the dashboard.
To do this, there are two methods, and the first one is to use a plugin! Install the plugin called "Disable Site", which disables the entire front end of your website and allows you to add a short message to visitors. Meanwhile, the back end of your site is available for you to view posts, change code or work on new projects.
The second method is to see if your theme has an under-construction page. This does the same thing and can be found under the Theme Panel on the Dashboard sidebar.

But if you're someone who's looking to simply permanently delete their website from the internet, there's a way to do that as well! First (as always), we recommend you download a backup of your website just in case you ever change your mind. To delete the site, visit your WordPress hosting account's dashboard and find the File Manager. Navigate to the root directory and delete all of those files.
Next, using a robots.txt file you can block your site from being scrolled by search engines.

User-agent: *
Disallow: /

If your site isn't self-hosted but is hosted on Wordpress.com, navigate to settings at the bottom of the side panel and click Delete Site at the bottom of the screen. But be warned (again), this is a permanent action and will remove ALL content from WordPress!

Deleting a website and starting over is thankfully easy with WordPress. Just remember to back up before you do anything as always!