In this section, we are going see what is SSL and why we need one?
SSL encrypts communication between the user and the server and provides security to your website. You need SSL Certificate installed on the server to use SSL.
If you are accepting credit card payments on your website or if you have having confidential data then you will need SSL Certificate for secure connections. It is also used to protect passwords in the secure login page. If your website's payment processing is done by third party websites like PayPal, Google Checkout, etc then you don't need to have SSL Certificate, since your website is not the one transmitting & storing credit card details.