General information

Now that you’ve finished installing Drupal 8, you can add additional functionality to your site by installing modules, or customize the look and feel by installing themes.

The standard Drupal core installation has limited features and looks fairly plain. However, Drupal is designed to be modular, making it easy to extend with additional modules and themes.

Each of the many modules and themes available on Drupal.org is called a “project,” and all are free. They’re often referred to as “contrib” because they are contributed by other members of the Drupal community, just like you.

In many cases, you’ll find that someone has already created and uploaded a project on Drupal.org that provides exactly what you need.

The process of finding and importing a module or theme into your site is essentially the same for both.

Modules

Modules provide the functionality of your site. “Core modules,” included in the standard installation, offer all the key features that most websites require.

However, not all core modules are enabled by default. So before searching for contrib modules, explore the list of available modules on your site’s “Extend” page to see if any core module already provides the functionality you’re looking for.

The Installing Drupal 8 Modules page is a comprehensive beginner-friendly guide. It contains useful information for both contrib and core modules.

Themes

If your primary interest is in installing a new theme, the Installing Modules page includes detailed instructions on finding and importing a project, whether it’s a module or a theme. Currently, the Installing Themes page is incomplete, but you can follow it after the theme is imported to your site.

Custom Projects

You should not directly modify core modules or themes, as those changes will be overwritten with each Drupal core update or security patch, which are released approximately every month. Instead, look for a contrib project that meets your needs or create your own custom project.

For more detailed information on developing or customizing existing projects, visit:

• Modules: Developing Modules with Drupal
• Themes: Theming and Front-end Development with Drupal

Warning

Back up your site and test the backup to ensure it works before using a module you haven’t used before, especially if it’s listed under “Other releases” or “Development releases” and not yet deemed stable for live (production) use.

Before using a contrib module for the first time, you should back up your site—especially the database—and record the Drupal core version it was using.

Most importantly, always test a contrib module on a test site (also known as a “development site”), not your live site, in case the module causes issues or breaks functionality.