Besides creating new questions from the quiz page or Question Bank, you can use the Create menu in the Confluence header:

  1. Click Create in the header
  2. Select the Quiz question blueprint
  3. Create the question as described in the points 3-7 here.

When you navigate to the Create menu while being on a quiz page or some question page, a new question is created with attachment to the quiz you were in.

If you create a new question via the Create menu while being on any other Confluence page, a new question will be created in your space with no attachment to a quiz, but will appear in Question Bank.