Headless CMS is a CMS that has no frontent, therefore you decouple the creation of content from the representation.
This opens up that you can change your representation technology easier.
They often use some sort of API to make the content that was created with the CMS available.
I hope this short explanation helps!
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.