HTTP stands for Hypertext Transfer Protocol. It basically means that it is a protocol, used for transferring data across the network.
HTTPS is the encrypted version of HTTP, i.e an SSL certificate is used to encrypt requests and responses. These HTTP requests are generated by the user’s browser when interacting with certain properties, like clicking on a link.
The browser will create and send the required requests in order to obtain the correct information to render the page for the user to view.