I'm using emacs 25.1.1 with the prelude config. In Atom I used to have a setting that made my lines wrap at 80 characters (without cutting words) for better readability. I've searched on the web for something similar for emacs but I have not found anything. Any ideas on how to do this?
auto-fill-mode is what you're looking for. You can enable it automatically for editing text by adding this to your config:
(add-hook 'text-mode-hook #'auto-fill-mode)
You can customize how long lines in your text documents should be by customizing the
fill-column variable. For example:
(setq-default fill-column 80)
If you want to to make sure that lines don't split on your screen as you're typing things, you can set up visual line mode.
To enable this for code files add:
(add-hook 'prog-mode-hook #'auto-fill-mode)