Drupal documentation

Drupal 6, 7, 8, 9, 10 and maybe sooner than we think, 11. Drupal 6 is very different from Drupal 11, as you can guess. A Google search for a simple problem will likely return an answer to your problem, but that answer will likely be from stackoverflow, answered 7 years ago on an old version of Drupal.

You can of course try your hand with ChatGPT, but you might end up with some frankenstein code that will never work, no matter on which version of Drupal you're working on.

While it might not answer all your question yet, there's been an ongoing initiative to make a Drupal book, with updated examples with chapter with a dedicated focus (like how to work with batch and queue, how to work with the Config, etc).

This is an open-source book, which can be contributed over on Github. Drupal also being open-source, it's always easy and fun to read the source itself instead of the documentation, but the book might help give you some guidance on what part of Drupal to look at, when you stumble on a bug.