apache 2 change error page code example

Example: error page apache2

<VirtualHost *:80>
    ServerAdmin webmaster@localhost
    DocumentRoot /var/www/html

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined

    ErrorDocument 404 /custom_404.html
    ErrorDocument 500 /custom_50x.html
    ErrorDocument 502 /custom_50x.html
    ErrorDocument 503 /custom_50x.html
    ErrorDocument 504 /custom_50x.html
</VirtualHost>