Categories provide an easy way to group Lists into a "bucket". If you don't want your recipients seeing the details of your public Lists, create Categories and place your Lists into the Categories. For example, you might have five different Lists that relate to tips or tricks for your product/service. You could assign each of the five Lists to a new Category, called "Tips & Tricks". Now when a recipient wants to unsubscribe, they could choose to unsubscribe from only the Tips & Tricks category, which would unsubscribe them from all five Lists in the Category.
You can manage your Categories from the Email Marketing page in the admin panel. To reach the page,
On this page, you will see your organization's Categories. You can edit or delete existing Categories, and you can add a new Category by clicking the green New button.
When creating a new Category, you only need to enter a name and optional description. When you're done, click Save.
You can add a List to a Category when creating a new List or editing an existing List. To access add a List to a Category,
To enable Categories on your unsubscribe page, flip the Categories switch on your unsubscribe template. Your email recipients will see all of the Categories containing Lists and can choose which to unsubscribe from.
Main Article: Custom Unsubscribe.