How to show a 404 page in WordPress?

@alvera_smith 1. Create a new 404.php file in your WordPress theme directory and add a custom message or design.

1. Activate a dedicated error page plugin such as the 404page Plugin.
2. If you are comfortable working with code, try customizing the 404 message in your .htaccess file.
3. If you are running a multi-site network, you can use the Super Admin to redirect visitors to a unique 404 error page.
4. Use a custom permalink for your 404 page. For example, you could use www.example.com/404 page.