Categories are labels you attach to blog posts (and pages) so they can be grouped and filtered on the site – the Blog List module shows a post's categories and lets readers filter by them. There are two separate sets: Blog Categories (/admin/blog/categories, in Website > Blog) and Pages Categories (/admin/pages/categories) – but both routes actually load the same admin screen and are gated by the same permission.

To manage: open the list (columns ID, Name), click + Add New Category, enter the Name (max 100 characters, required – "Name empty" otherwise) and Save. Editing works the same way via the pencil icon. Categories cannot be deleted from the admin in the current version. Assign categories to a post in the post's Settings > Categories multi-select.