Even though iOS prides itself on being one of the most user friendly mobile experiences on the planet, that doesn't mean everything is always obvious. For those with visual impairments, some menus and places that you can tap on the screen may not immediately jump out at you. Luckily, iOS comes equipped with some great accessibility options that includes the ability to enable button shapes so menu items you can interact with are more readily obvious. In order to use them, you've just got to enable them first.
How to enable button shapes on iPhone and iPad
Launch the Settings app on your iPhone or iPad.
Tap on General.
Tap on Accessibility.
Turn On the option for Button Shapes — it's about half way down the page.
That's it. You should instantly notice that interactive menu items now are highlighted gray. Actionable items such as send buttons and menus will also display an underline indicating that you can tap on certain options to perform an action. Button shapes and underlines should work for all built-in apps and some third party apps, but be aware that not all of them will.