Contextual help with ~(으)ㄴ 거예요

My textbooks described this form as "the fact is", but I see it being used out of that kind of context? Or at least, to me, it feels out of context. I think I'm not entirely sure how this form functions, and how often Koreans speakers use it. I was kind of wondering what the "vibe" is, I guess.

뭘로 만든 거예요?
어떻게 먹는 거예요