Your code, your text editor
Atom is the text editor that I recommend using for now. There are many text editors for coders and people tend to have strong opinions about them, but I'm recommending Atom because it's very beginner friendly, yet still very powerful, and because it's really a great text editor. It also happens to be free. Don't overthink this... Atom is an excellent editor and there are more important things to worry about right now. You will have the right to have nerd-arguments about text editors after you've built a few applications. People will tell you that you're an idiot if you're not using their favorite text editor (Vim, Emacs, Sublime Text, etc)... You can safely ignore all of this and learn how to use Atom.
One of the reasons I recommend starting with Atom is that it provides you with the basic features that you'll want in a code editor without needing to install plugins or add-ons. That said, you can look around in the Atom Packages repository and see if anything looks useful.
Here are a few that I think you should install to get started:
Emmet is a very useful plugin that you should spend a little bit of time learning how to use. I recommend watching the video demo and referring back to the cheat sheet in order to understand what it does and how to use it.
There are tons more plugins that will be useful to you later, but there's no need to overcomplicate things right now. Just poke around Atom and get familiar with the interface. You should also try and learn as many keyboard shortcuts as possible from the beginning. I recommend using a site called Shortcut Foo. They have little drills that teach you keyboard shortcuts for all kinds of programs, including Atom. If you spend 10 minutes a day on these, you will have mastered the basic commands in a few weeks. You should try to use your mouse/trackpad a seldom as possible, as it is extremely slow compared to using the keyboard. Anything you can do with a mouse/trackpad in Atom can be done with a keyboard shortcut. Make this your mission for a few weeks.