Page not found (404)
A 404 page is what users see when they try to visit a page that does not exist (for example, because they clicked a broken link, the page has been removed, or they entered the wrong URL). It is called a 404 page because the web server returns the status code 404 when a requested page cannot be found.
The text on the 404 page can be customized by editors.
A well-designed 404 page is more important than you might think. Users should clearly understand that they have reached the wrong page, while also receiving help to find the right one. For example, you can include links to the search page or other key pages on the website or intranet.
By providing clear information on the page, you can also ask users for help by inviting them to describe how they ended up on the 404 page. This allows you, as an editor, to identify and fix the issue.