Redirect Website to a particular file

1) create a file which file you want to redirect(eg. filename.php).
2) create .htaccess file.
3) add the following code in the .htaccess file.
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} -s [OR]
RewriteCond %{REQUEST_FILENAME} -l [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^.*$ filename.php [NC,L]