A few things can be stated. First, this is Mandarin Chinese and it is also called Putong hua. This is important to point out, because there are so many dialects in Chinese. Remember there are over one billion Chinese!
Second, it literally means you well? So, it is an interrogative, that is, it expects a response. Third, it is singular, that is, only one person is in view. We do not differentiate second person singular and plural in English, but in Chinese you certainly can. If we said, "nimen hao ma," then this would mean - Are you all well?
Fourth, this is used as a greeting and it is probably the most common greeting in China. You can use this statement any time of the day on almost any occasion. Good luck with further Chinese learning. In the future and even now, it will be one of the most important languages to learn.