The Questions block in the software can be detached and sized or moved anywhere you want on your monitor(s). To detach the Questions block, click the icon NEXT TO the "X" found to the right of the word "Questions." Once detached, you can change the size by dragging the sides of the box or move it by dragging the title bar.
You can also minimize the rest of the webinar software block by clicking the white arrows on the left edge of the block. You can't change the text size in the questions box except by changing the resolution of your display through your computer's Control Panel.