Drupal 8: hook_form_alter explained

This Drupal 8 code snippet provided is a hook implementation that alters a specific form in a custom module named myModule.

Here's a breakdown of what the code does:

1. Function Hook: The function `myModule_form_alter()` is designed to modify forms and is part of the Drupal form API. It's invoked for every form on the site, allowing custom alterations based on the form ID.

2. Target Form: The form alteration targets the form with the ID `commerce_billing_schedule_edit_form`.