The SSL Certificate (Secure Sockets Layer) is a protocol that ensures the users who visit your site to browse in a safe environment. This security can be noticed by the user through the closed padlock displayed in all browsers and the term https in the address etc.
The communication between the site and the end user is protected by encryption. Thus, your valuable data such as login information, forms, emails and credit card transactions are transmitted securely. It helps to prevent data from being intercepted by unauthorized users.