With Joomla it is really easy.
Log in to Joomla as the administrator, and then:
For Joomla 3, on the top menu bar, click System, and then click Global Configuration.
Click the Server tab.
Under Server Settings, in the Force SSL list box, select
SSL is now enabled for Joomla.
Note: A SSL certificate must be already installed on the account. Every shared hosting account on Hosting Nation comes with a basic SSL certificate. If you require more trust or different configurations, check out our SSL products.