If not using WordPress you may need to create your own .htaccess file for this.
So how do you forward?
http://example.com/
http://www.example.com/
https://www.example.com/
to
https://example.com/
Create a new .htaccess file and enter the following content:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP:X-Forwarded-Proto} !https [OR]
RewriteCond %{HTTP_HOST} ^www\. [NC]
RewriteRule ^(.*)$ https://example.com%{REQUEST_URI} [R=301,L,NE]
</IfModule>
<IfModule mod_headers.c>
<FilesMatch "\.(jpg|jpeg|png|gif|swf|flv|mp3|ico|pdf)$">
Header unset Set-Cookie
FileETag -INode MTime Size
Header unset Last-Modified
Header set Cache-Control "max-age=31536000, public, must-revalidate"
</FilesMatch>
<FilesMatch "\.(js|css)$">
FileETag None
Header unset Set-Cookie
Header set Cache-Control "max-age=2592000, public, must-revalidate"
</FilesMatch>
</IfModule>
As you can see there is also some other code added to prevent overweight from cookies and controlling a bit of caching.
Have a nice day!