Hi, about (Ma ) in Ni Hao Ma, it is a mood word, used in questions.Usually, it placed at the end of a sentence.

Ni Hao Ma =你好吗？= How are you or How do you do?

ma is the modal words at the end to indicate a question . Sentences using tone to indicate doubt. su as he is here --------Is he here? hi hao -----------------------ni hao ma ?

"ma" is a modal praticle. It is used in interrogative sentence. Ni hao ma?= How are you?

"你好吗?" means "how are you!"