HTTP stands for Hyper Text Transfer Protocol and it is an communication protocol. Shortly, HTTP can be thought of as a key that allows us to connect to websites.And there is HTTPS. It means Secure Hyper Text Transfer Protocol. HTTPS makes the site you visit secure as it encrypts the data exchange between the user and the server.
In summary, all sites with https:// at the beginning have SSL certificates, they protect your informations against possible security problems.