HTTP is stateless and application label protocol. HTTP is the mode by which web pages are communicated across the internet.It specifies the requests that a client can send to a server and responses that server can send as reply.
Most of the conversations help on the web between client and server are held using the HTTP protocol, which allows simple simple request and response generation. The client sends an HTTP request nad gets a HTTP response. If you are a web server you speak HTTP. When a server sends a html to client, it sendins using HTTP protocol. HTTP runs on the top of TCP/IP.