How many types of points of view are there in the narrative in "Thank You Ma'am" by Langston Hughes?
In my opinion, the narrator in this story is a third person narrator, but one who is omniscient. The narrator does not always make use of his (or her) omniscience, but he is able to use it at times.
The narrator is clearly a third person because the story is not told from the point of view of anyone who actually takes part in the events that happen. The narrator does not say, "And then I grabbed her purse..." or anything like that.
The narrator is omniscient because he knows what the characters are thinking. He knows, for example, that Roger wants Mrs. Jones to trust him.
So I suppose you could say the narrator is limited at times (when he just says what is happening) but is omniscient at others (when he says what a character is thinking.