Increase Font Size on iPhone is easiest when you use the iPhone feature that directly controls the task instead of changing several unrelated settings.
- Open Settings.
- Tap Display & Brightness.
- Tap Text Size and move the slider to the size you prefer.
- For larger choices, go to Settings > Accessibility > Display & Text Size > Larger Text.
- Enable Larger Accessibility Sizes if you need the expanded range.
Apps that support Dynamic Type respond to these settings. Some apps use their own text-size controls, so one setting may not change every piece of text.
If only one app has tiny text, check that app’s own settings before increasing text everywhere. Control Center can also provide a Text Size control that lets supported apps use different text sizes.
When finished, verify the result in the app or setting you changed before making additional adjustments.