HELP with Wordpress?

I'm working on a blog these days using a simple Wordpress theme. Not much functions. The problem is that it doesn't show the category in post thumbnail. How can I make this happen? Code or plugin?

Something like this would be awesome
https://imgur.com/a/ySWoVf5

Looks like some CSS magic is needed to accomplish that. Depending on the theme some PHP code too, but that would involve the sharing of a bit more info about the current theme.

The latter can be done here, not necessarily via a dm.