How to change the appearance of button shapes in iOS 12 on iPhone/iPad/iPod Touch

When 'Button Shapes' is enabled buttons are presented as underlined, blue text. 

1. Open the ‘Accessibility Settings’: Settings > General > Accessibility. (See the article Open Accessibility Preferences on this website for more information.)
2. On the Accessibility screen, scroll down to the ‘Vision’ section and tap the toggle switch for ‘Button Shapes’.
   
3. The image below shows the appearance of buttons when ‘Button Shapes’ is and isn't enabled.
   
4. When happy with your settings, either tap the back button in the top left of the screen to return to the main ‘Accessibility’ settings screen, or press your device’s ‘Home’ button to return to the home screen.