First, select the text—just tap on it in the preview screen or in the timeline. While it’s selected, you can resize it by pinching on the preview screen. You can use the label "Size" displayed above the text as a guide.
😎 Plus you can use the grid to position the text on the preview screen.
✍️ While the text is selected you can change the Font, Text, or Background Color, increase the Border or Stroke width, and choose another font.