To make the text size bigger or smaller on an iOS device:

1. Open your device’s Settings app
2. Tap General
3. Tap Accessibility, then tap Larger Text
4. Tap Larger Accessibility Sizes for bigger font options
5. Use the slider to select the font size you want

To make the text size bigger or smaller on an Android device:

1. Open your device’s Setting app
2. Tap Accessibility, then tap Font Size
3. Use the slider to select the font size you want