The Instructions Behind Everything
Every app, website, game, and program you use is built from something called computer code. We hear about coding and programming constantly, and they are among the most important skills of the modern world. But for many people, code remains a mystery, imagined as a baffling screen of symbols. In truth, the basic idea of computer code is straightforward.
A Computer Needs to Be Told What to Do
A computer is a powerful machine, but on its own it does nothing. It has no ideas and makes no decisions by itself. It can only follow instructions. For a computer to do anything useful, whether showing a web page or running a game, something has to tell it precisely what steps to take. Computer code is exactly that: the set of instructions a computer follows. Writing those instructions is called coding or programming.
A Special Kind of Language
Code is written in a programming language. A programming language is a special, carefully designed language used to give instructions to computers. Unlike human languages, it has very strict and exact rules, because a computer needs precise, unambiguous commands and cannot guess what you meant. There are many different programming languages, each with its own style, but they all serve the same purpose: letting a person write instructions a computer can carry out.
From Human Writing to Machine Action
There is one more layer to understand. Deep down, a computer only truly understands binary, the ones and zeros. Programming languages, however, are designed to be much easier for people to read and write. So when a programmer writes code, that code is translated into the basic instructions the computer's processor can directly execute. The computer then follows those instructions, one after another, extremely fast. That is how lines of written code become a working program on your screen.
Source
This article was written using information from Wikipedia.