First, understand this: The word mood has nothing to do with frame of mind, as in happy or sad. It actually refers to mode, which is the attribute of a verb suggesting the speaker's attitude toward the action expressed.
The mood of verbs shows how the speaker regards the utterance. The speaker might regard the utterance as a statement: that's the indicative mood. The speaker might ask a question: that's the interrogative mood. The speaker might issue a command: that's the imperative mood. Or the speaker might state a possibility, hope, wish, or hypothetical: that's the subjunctive mood.
In the interrogative mood, you don't change the form of the verb. Instead, you invert the auxiliary verb and place it before the subject. The main verb comes after the subject. Here are some constructions of the interrogative mood:
Is he having any fun? Do you think he will win? Have the women finished the match?