HTTP (Hypertext Transfer Protocol) is the standard protocol used for transmitting data over the internet. However, it is not secure as the data being transmitted is not encrypted, which means that it can be intercepted and read by anyone who has access to it.

On the other hand, HTTPS (Hypertext Transfer Protocol Secure) is a secure version of HTTP that uses SSL/TLS encryption to protect the data being transmitted. This makes it much harder for anyone to intercept and read the data.

In general, it is recommended to use HTTPS for your Joomla website, especially if you are collecting sensitive information such as personal or financial data. HTTPS can help protect your website and your users from various security threats such as hacking, phishing, and identity theft.

While HTTPS may require additional setup and maintenance compared to HTTP, the benefits of using HTTPS far outweigh the costs. In fact, many search engines and web browsers now prioritize websites that use HTTPS over those that don't, which can help improve your website's visibility and credibility online.

To force your Joomla site to use HTTPS, you can follow these steps:

1. Log in to the Joomla administrator panel.
2. Go to System > Global Configuration.
3. Click on the Server tab.
4. Under Server Settings, set the Force HTTPS option to "Yes".
5. Save the changes.

This will force your Joomla site to use HTTPS for all pages, which will help ensure that the data being transmitted is encrypted and secure. However, please note that you will need to have an SSL certificate installed on your server in order to use HTTPS. If you don't have an SSL certificate, you will need to obtain one from a trusted certificate authority and install it on your server before you can use HTTPS.