Drupal is a sophisticated platform, and from the glimpse provided in this chapter, we can already see that there are numerous systems and structures to keep track of. In this section, I will provide tools that simplify or streamline the development process.
Going forward, I assume that you have your own web server stack and your own PHP development tools. However, if you are just getting started, you may want to look at Acquia Dev Desktop from Acquia (http://acquia.com). It offers entire application stacks to get you started on Windows, Linux, or macOS X. Alternatively, if you are even just a bit more advanced, you can consider the Drupal VM (https://www.drupalvm.com/), a Vagrant and Ansible-based local development environment ready for Drupal.
Finally, the most flexible development environment in my opinion is the Docker-based one. You can easily get started with a pre-made and well documented stack here: https://github.com/wodby/docker4drupal.
As for a code editor, I personally use PhpStorm (as many others do), but you are free to use whatever IDE you want because Drupal itself doesn't require anything special. Do, however, use some sort of an IDE because it will make your life much easier.
Additionally, while running a PHP debugger is certainly not necessary, you may find running Xdebug or the Zend Debugger to be useful. I personally recommend a PHP debugger wholeheartedly, not only for debugging itself, but also for understanding the processes that happen under the hood.