If you owned a website, it is better to have a SSL certificate installed for it. By having SSL, you can force your website visitors to connect to your website using HTTPS instead of HTTP.
When they connect to your website using HTTPS, all communication between the website and the visitors will be encrypted. No one can intercept and read the data in between. That is why, most online shopping websites, or online banking portals are using HTTPS connection to protect their customers login credentials and information.
SSL certificate cost you money and you need to renew it every year. The price can range as low as $8USD and can be up to more than $200USD a year.
Some web hosting providers provide free SSL certificate to their customers. And the SSL certificate will be auto-renewed before the expiry date.
But, if your web hosting provider does not provide free SSL certificate, you can get it for free from https://www.sslforfree.com
But before you can get the SSL certificate, you need to verify you are the owner of your website. There are several ways to verify the ownership, but I prefer manually upload the files given by SSL For Free. Just upload the files and done.
After the verification is successful, you will be given the SSL certificate where you can install to your website.
But just a reminder. The SSL certificate is valid for 3 months. So every 3 months, you need to renew your SSL certificate and redo the same process manually.