Normally, I drop world wide web when typing within the URL. Frankly, one important site I visit, don't support such shorted URL and I wish to request these to repair it.

Is really a solution a configfile fix? Or will it need a special provider-related service?

It is a virtual host configuration or perhaps a DNS C title, for the way they've it set up.

Suggest they've created a C Reputation for the non-"world wide web" version of the URL.

Should they have Rewrite Engine enabled, they are able to create .htaccess file with this particular rule

RewriteEngine on

RewriteCond % ^example.com$ [NC]

RewriteRule (.*) http://world wide web.example.com/$1 [L,R=301]

By doing this everybody who involves http://example.com is rerouted to http://world wide web.example.com instantly.

When they have the VirtualHost container they can just add the ServerAlias directive:

ServerAlias example.com

This can require no redirection so it will likely be faster towards the user.