WordPress allows you to add descriptions for your categories. To add the description for categories, go to Posts > Categories, then edit the category and add the description. However, if you are creating the new category then you can simply add category name and description.
Spacious Premium version allows you to display those description, all you need to do is:
- From your WordPress Dashboard, navigate to the Appearance > Customize > Content > Blog/Archive
- Scroll to locate Category Options.
- Put a checkmark on Activate Term Description.
- Click on Publish.