HTTPS (standing for Hypertext Transfer Protocol Secure) is an encrypted protocol through which HTML pages are sent. It adds an extra layer of security to typical HTTP communications, using what’s called the Transport Layer Security (TLS) protocol.
In 2014, Google announced that this extra layer of security would become one of many determining factors in a website or webpage’s rank. With all else being equal between two different webpages, the page with HTTPS, rather than merely HTTP, would rank higher. HTTPS is seen to protect Googles’ customers and search engine users from eavesdropping attacks, it’s a quick and easy way for a user to determine whether they want to trust the website.