system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does code work? (C++, C#, Java)

I somewhat understand code, only to the point that I know you can design apps with it though. I know that there are different "languages" for different things you're doing, but I don't understand what and why there are different ones. 

Main questions:
What is code exactly? 
Why is there code?
What are the different "languages" used for? 
What could one make knowing code?
gpt
> What is code exactly?

Code is the instructions that tell a computer what to do
 
> Why is there code?

Without code, we wouldn't be able to get a computer to do anything. Or perhaps we would, but it would have to be built for a single task. It's the code that enables us to take advantage of the flexibility of a computer, to get it to do whatever we want.

> What are the different "languages" used for? 

Some are fast and powerful, but difficult to use. Others aren't quite as powerful, but are much easier, making them better for beginners, but also better for writing simple software that doesn't need to do anything complicated (because it's quicker and easier to write in these simpler languages).

Some are specifically designed for a particular purpose - for using in web pages, for doing mathematical tasks, for handling lots of data. Others are more general-purpose.

And very often there's more than one language for doing exactly the same thing.

> What could one make knowing code?

Every single thing your computer does, is made using code. Every single thing it ever could do, could be done by writing code to do it.