Learn French: Est-ce que tu as une question ?

It acts just like "Do" in English here. Literally, it translates to "is it that," but it's simply a set phrase used to turn a regular statement into a question. Since tu as means "you have," adding est-ce que at the start changes it to "Do you have?".

This lesson is about adding question words to est-ce que. How would I do that here?

This specific sentence is a simple "yes or no" question, so it just starts with est-ce que. To add a question word like pourquoi (why) or quand (when), you simply put it at the very beginning of this exact sentence! For example: Pourquoi est-ce que tu as une question ? (Why do you have a question?).

Could I just say Tu as une question ? without est-ce que?

Yes, you can! In everyday spoken French, it's very common to just use the normal sentence order (Tu as une question) and make your voice go up at the end to show it's a question. However, using est-ce que is also extremely common and is a great, polite way to ask a question in any situation.

Why is it une question instead of un question?