Adjust the display and text size on iPhone
If you have color blindness or other vision challenges, you can customize the display settings to make the screen easier to see.
Use display accommodations
Go to Settings > Accessibility > Display & Text Size.
Adjust any of the following:
Bold Text: Display the text in boldface characters.
Larger Text: Turn on Larger Accessibility Sizes, then adjust the text size using the Font Size slider.
This setting adjusts to your preferred text size in apps that support Dynamic Type, such as Settings, Calendar, Contacts, Mail, Messages, and Notes.
Button Shapes: This setting underlines text you can tap.
On/Off Labels: This setting indicates switches turned on with “1” and switches turned off with “0”.
Reduce Transparency: This setting reduces the transparency and blurs on some backgrounds.
Increase Contrast: This setting improves the contrast and legibility by altering color and text styling.
Apps that support Dynamic Type—such as Settings, Calendar, Contacts, Mail, Messages, and Notes—adjust to your preferred text size.
Differentiate Without Color: This setting replaces user interface items that rely on color to convey information with alternatives.
Smart Invert or Classic Invert: Smart Invert Colors reverses the colors of the display, except for images, media, and some apps that use dark color styles.
Color Filters: Tap a filter to apply it. To adjust the intensity or hue, drag the sliders.
Reduce White Point: This setting reduces the intensity of bright colors.
Auto-Brightness: This setting automatically adjusts the screen brightness for current light conditions using the built-in ambient light sensor.
You can also apply these effects to only the contents of the zoom window. See Zoom in on the iPhone screen.