http referred as Hyper Text Transfer Protocol is an application protocol for distributed, collaborative, hypermedia information systems. It is the foundation of data communication for the World Wide Web, where hypertext documents include hyperlinks to other resources that the user can easily access, for example by a mouse click or by tapping the screen in a web browser. It was developed to facilitate hypertext and the World Wide Web.
A later version, the successor HTTP/2, was standardized in 2015 and HTTP/3 is its proposed successor Internet Draft, that builds on HTTP/2 and is now supported by major web servers and browsers over Transport Layer Security (TLS) using Application-Layer Protocol Negotiation (ALPN) extension where TLS 1.2 or newer is required.
HTTPS means Hyper Text Transfer Protocol Secure. Basically, it is the secure version of Hyper Text Transfer Protocol. Communications between the browser and website are encrypted by Transport Layer Security (TLS), or its predecessor, Secure Sockets Layer (SSL).
Hypertext Transfer Protocol Secure is an extension of the Hypertext Transfer Protocol. It is used for secure communication over a computer network, and is widely used on the Internet. In HTTPS, the communication protocol is encrypted using Transport Layer Security (TLS), or, formerly, its predecessor, Secure Sockets Layer (SSL). The protocol is therefore also often referred to as HTTP over TLS, or HTTP over SSL.
The principal motivation for HTTPS is authentication of the accessed website and protection of the privacy and integrity of the exchanged data while in transit. It protects against man-in-the-middle attacks.