Custom Modules are reusable modules that can be added to HubSpot drag-and-drop templates and customized with simple fields at the page level. They allow your developer to code advanced features for your pages, while still making it simple for you to customize the content. When editing a page with a custom module, you'll be able to click into the module to view and edit the available fields.
In the screenshot below, you can see an example of an accordion custom module, which has been coded in the Design Manager and styled with effects to expand when clicked. In the page editor, you can click on the module to edit the content and make styling choices using simple fields without touching the code.
Each custom module is reusable, meaning it can be added to any page and customized for each use case. It can also be added multiple times on the same page to create FAQs, Team pages, etc.
For more information about creating custom modules, check out this article.