Henry I. answered 06/18/19
Experienced, Patient Math and English teacher
Good question! When you mean a question to be more of a statement, as you describe it, you are asking a "rhetorical question." In other words, the speaker doesn't wish an answer, as he/she is actually making a statement.
Rhetorical questions DO use question marks. Ordinarily, the rhetorical nature of the question will be self-evident. But if you feel it's insufficiently clear, then you must provide further explanation.
Best wishes!