How to change the color of the button of the screen in Samsung Galaxy S8+?

Navigator bar changes the color or button layout of the navigation bar that appears at the bottom of the screen.

Navigate to Apps → Settings → Display → Navigation bar → Choose color → DONE

Pictorial representation of the above settings are as follows :  

a). From home screen, swipe up to launch Apps.

b). Tap Settings.

c). Tap Display.

d). Scroll up the screen.

e). Tap Navigator bar.

f). Tap More color to choose the color.

g). Tap any color. Tap DONE.