It transforms predicate part into noun form, which means nominalization, 명사화 or 명사형 종결, and the transformation will have another tone such as notification. 나는 집에 갔다 -> 나는 집에 갔음 In addition, it is used to list some detail information in reports. p.s. I think that "좀" is in another category. If you give me a full sentence, I can give you an explanation.

Hi, Besides the previous answers, I would like to add another point. These days many Korean internet/smartphone users (including me) use noun forms of verbs instead of the proper endings in order to make sentences shorter in SMSs or while chatting. Thus, you might think of them as a slang. Cheers.