How do translate a language in a plugin?

Hi There

I don't know if this the right forum? But I have a big issue in regards to language and my present plugin for my blog. My website is in Danish but plugin is in english and as far as I can see I haven't got the possibility to translate the language snippets to Danish anywhere. So now the styling is English and the blog texts are in Danish.

Pls see examples here https://nextrekruttering.dk/blog/

as you can see texts like "recent posts","comments" and "read more" are in English

Greatfull for any help or suggestions