Being an important part of almost every WordPress website, the Opinion theme provides some very nice features for category templates. To set the default layout settings for your categories, go to Theme Options -> Category Template.
Category display settings and image
The same as for single posts and pages, you have the options to change the display settings for each category separately, if for any reason you need different layouts for different categories. In your admin panel, go to Posts -> Categories to access the separate options per each category.
Also, one of the additional features is the ability to choose a featured image for each category which will be displayed in category modules or in a specific category layout (cover, for example).
Watch a demonstration in this short video: