There are 2 great anecdotes about these protocols that emphasize their essence:
"I know a great joke about UDP, but it is not a fact that it will reach you." "I know a great joke about TCP, but if it doesn't reach you, I'll repeat it."
TCP is a data transport protocol. To send packets, he needs to establish a network connection in advance. After the packet has been transmitted, the protocol will require a transmission report, success or failure. Monitors the load on the network. Therefore, this protocol is considered more secure and reliable.
UDP is also a transport protocol for data transmission. It doesn't need to install anything in advance to transfer packages. I sent the packages, and what happens next with them - no difference. Doesn't control anything, doesn't ask for anything in return, doesn't guarantee package delivery. Naturally less reliable, but therefore faster. Therefore, it is used for big data transmission where "interference" is allowed. For example, photo, video, audio information, online game client.