Which change requires code customization in Magento?

In Magento, certain changes can typically be made through the admin panel without requiring any code customization. For example, displaying a banner in the content area can be achieved using the CMS features available in the admin interface, allowing users to add or modify content without touching the underlying code. Similarly, changing a footer link is also manageable through the configuration settings provided in the Magento admin, where users can easily edit links without needing to write any new code.

Adjusting the layout of product pages, such as switching from a one-column to a two-column layout, can often be accomplished by utilizing the layout update functionality and changing settings in the admin panel. This is possible through flexible layout management available in the system, which allows merchants to adjust how pages are displayed based on their theme without custom coding.

Therefore, the correct response is that none of these changes require code customization, as they can all be achieved using the built-in features within the Magento admin interface. This makes Magento a flexible platform, allowing non-developers to make necessary adjustments with relative ease.