Http means ''Hyper Text Transfer Protocol''. It is the protocol used by world wide web which defines how message s are formatted ,transmitted and what action web servers and browsers should take in response to various users command .
let suppose you enter a website URL in your default browser, this is the phase when you actually send an http command to web server directly to fetch and transmit the web page you requested for.
Https means ''Hyper Text Transfer Protocol Secure''. It is the protocol used for secure communication between user command and primary web server because it enable encrypted communication and secure communication between them. It is used to provides services for secured sensitive data , transaction , billing & user logins. It uses SSL & TLS encryption to avoid hacker and attacker from the website.