When I write the Sub Page Link To Browser It gives 404 Error

Hi there,

I could suggest using the following .htaccess rules:

<IfModule mod_rewrite.c>
  RewriteEngine On
  RewriteBase /
  RewriteRule ^index\.html$ - [L]
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{REQUEST_FILENAME} !-l
  RewriteRule . /index.html [L]
</IfModule>

Note that you would need to enable AllowOverride in your Apache virtual host:

    <Directory "/var/www/html/">
            Options Indexes FollowSymLinks
            AllowOverride all
            Require all granted
    </Directory>

Let me know how it goes! Regards, Bobby