What do I need to start coding?

Source code is the human-readable version of our program. A constant across programming languages is that source code is just plain text (the text you type is the only content of the file you create). Yes, you can write whatever program  you want by using the notepad application that is included in your computer. If you want to ease your work as programmer, then you may want to use a more specialized software such as a programmer text editor, or an Integrated Development Environment (IDE).

Source code files (commonly referred to as source files) have many different name extensions depending on the programming  files. For example, files whose name end with ".c" are files with C code, files with ".py" extension are used for Python programs, ".js" files contain Javascript code, and ".m" files are MATLAB scripts. Although they are used for different programming languages, they are all plain text files.

Writing source-code using a rich-text editor or a word processor may not work very well. The file that results after saving a text in one of these editors may contain much more information than your text itself. For example, let's write the words "Hello world!" (and make it bold, with size of 20 points, and blue), visualize it in WordPad, and in a plain text editor (notepad).

Observe how the plain text editor "sees" much more content than just the text we typed. A similar thing would happen with any other word processor.

So what the source-code to machine-code would really see, is the version we observe in the notepad. That version may not make any sense to such translator. Therefore, if we want to really know what we are going to pass, we better use a plain text editor.

Programmer text editors are also plain text editors. They just have some extra features added to them. Maybe the most popular ones are line numbering (displaying the line number at the left of the text), and syntax high-lighting (highlighting the special keywords from our programming language with different colors so the code becomes easier to read and navigate).

Integrated Development Environments (IDEs) are a set of programs that have the common purpose of helping us develop our programs. Some examples are:
 - Visual Studio,
 - Eclipse,
 - Code-Blocks,
 - Net-Beans,
 - Wing IDE,
 - Among many, many others...

All IDEs include a plain text editor. In addition, they may also include a project manager, which is used to navigate through our software project files easier than using a regular file explorer. They may have also an integrated shell for us to input commands or displaying the output of our program. There are infinite kinds of tools that may be included in an IDE, but these are the most common.

At the end, deciding what tool to use depends mostly on how comfortable you feel using it. Some people may prefer regular text editors over IDEs, or vice-versa. Most of the tools are free or have a trial version, so you can check what fits your needs and preferences.

PD: I prefer dark backgrounds as they tend to be more confortable to my eye by minimizing the amount of light that the screen emits.