Adjust iPhone per-app text size when one app is hard to read. Keep the rest of your phone comfortable while changing the app that needs attention.
Open the app-specific controls
- Go to Settings > Accessibility > Per-App Settings.
- Choose Add App and select the app.
- Tap its name to open its accessibility settings.
- Adjust the text-related options available for that app.
Apple supports separate color, text-size and motion settings for selected apps, including settings for the Home Screen and App Library.
When a global change is more suitable
If text is too small throughout your phone, open Accessibility > Display & Text Size > Larger Text. Larger Accessibility Sizes provides additional options, and Bold Text makes text heavier. Supported apps respond to these controls.
Choose a real screen for testing
Our suggestion: return to a screen you use every day, such as a long email or a list of appointments. Check both the smallest text and the buttons around it. A setting that looks good on a short heading may be less comfortable inside a busy form.
Make one change at a time. If you increase the text size and change several contrast settings together, it becomes harder to identify which adjustment helped. Keep a simple note of the starting settings if you expect to experiment.
Do not aim for the largest possible text
The goal is comfortable reading while keeping important controls accessible. If buttons become awkward or too little content fits on screen, reduce the size slightly and test again. Apple notes that very large text can make some app functions harder to tap.
A quick final check
Test the app in the lighting you normally use. Open a second app to make sure your wider setup still feels right. This approach is particularly useful when one app needs extra help but your overall phone layout already works well for you.
Source: Official support documentation. Interface labels may vary with software version and device.
Additional reference: Apple’s text-size guidance.