You might be thinking of a rhetorical question, which is a question asked to emphasize a point or create a dramatic effect, rather than to elicit an actual answer.
For example:
* "Is the sky blue?" This is not a question meant to be answered, but rather a way of stating the obvious.
* "How many times do I have to tell you?" This isn't a request for a numerical answer, but a way to express frustration.
If you're looking for another term, please provide more context about what you're trying to describe.