HTTPS is a secure version of the Hypertext Transfer Protocol, the essential method your browser uses to connect with websites. At the expense of a little speed, it adds a layer of encryption to data transfer, making the information harder to see by attackers on the same wireless network. In 2010, Gmail made HTTPS the default for all users, and Twitter did the same this year. Facebook users will have the ability to opt-out of HTTPS in their account settings. To see if the site youre on is using an HTTPS connection, just look at the address bar.”]
Source: https://www.csoonline.com/article/2132545/facebook-moves-all-users-to-https-for-added-security.html