Who invented the Internet?

No one person invented the Internet. Certain major contributors played important roles to achieve problems breakthroughs. The Internet as we know it today initially started being developed in the late 1960's.

Leonard Kleinrock was the first person to publish a paper about “the packet switching” in 1961. This was the essential idea for the creation of the Internet. Packet switching is the basic mechanism to transport packets (blocks of data) from one place to another by means of reading the address on the packet, much like the address on a postal letter. The packet switching replaces the older concept of "circuit switching”that holds a fixed physical end-to-end path to establish and keep the connection throughout the entire duration of a phone call. On the other hand, with packet switching, each packet freely selects the alternative paths between the source and the destination. One physical connection carries the packets mixing lots of different calls packets at the same time. The packets for thousands or millions of users can share a single physical connection to the Internet.
J.C.R. Licklider was the first to describe an Internet-like worldwide network of computers in 1962. Larry G. Roberts created the first functioning long-distance computer network in 1965 and designed the Advanced Research Projects Agency Network (ARPANET), which is the seed from which the modern Internet grew, in 1966.
The University of California LA school (UCLA) puts out a press release introducing the Internet to the public on the 13th of July 1969.
In October, the first Internet message was sent from the laboratory of Leonard Kleinrock who was a computer science Professor at UCLA. This connection not only enabled the first transmission that was made but is also considered to be the first Internet backbone. In 1973, Bob Kahn and Vinton Cerf invented the Transmission Control Protocol (TCP) that moves data on the modern Internet, and later published it with the help of Yogen Dalal and Carl Sunshine December 1974 in RFC 675. If any two people "invented the Internet," it was Kahn and Cerf - but they have publicly stated that "no one person or group of people" invented the Internet.
In 1978 TCP was split into TCP/IP driven by Danny Cohen, David Reed, and John Shoch to support real-time traffic. This allows for the creation of UDP. By 1983, TCP/IP was the standard and ARPANET began to resemble the modern Internet in many respects. The ARPANET itself was taken out of commission in 1990. Most restrictions on commercial Internet traffic ended in 1991.
Paul Mockapetris and Jon Postel introduced DNS in 1984.Tim Berners-Lee developed HTML in 1990, which made a huge contribution to how we navigate and view the Internet today. Tim Berners-Lee introduced WWW to the public on the 6th of August 1991. The Internet experienced one of its largest growths and today is accessible and used by people everywhere in the world.