Once you have purchased an SSL certificate for your website you can redirect your site to connect to the https version by creating a .htaccess file and placing it in your public_html folder.
In the .htaccess file add the following and replace the domain with your actual domain name:
#If the page is NOT secure, redirect to a secure page RewriteCond %{SERVER_PORT} 80 [OR] RewriteCond %{HTTPS} !on RewriteRule (.*) https://www.domain.com/$1 [R=permanent,L,NC]