What is an SSL Certificate and what does it do? I hear you ask.
An SSL certificate will keep sensitive information sent across the internet encrypted so that only the intended recipient can understand it. Any computer in between you and the destination server can see your credit card numbers, usernames and passwords, and other sensitive information if no SSL certificate has been installed. When an SSL certificate is active, the information and data is only readable by you and the destination server.
Google are now penalising websites that are not hosted with an SSL certificate and this will effect your page ranking. Most importantly from April 2018 browsers will note that your website is not secure before the visitor can visit your website and certain browsers will even stop access top your website.
To check if your website is secure view the padlock symbol displayed in the url.