You can change which keys are displayed in the Touch Keys bar, as well as how they’re displayed.
From the Home screen, touch and hold the Recent Apps Key (in the QuickTap bar) > Settings > Display > Home touch buttons.
Select the modification you want to change.
Tap Button combination to select which Touch Keys you want in the bar and their location within the bar. Choose from the Back Key, the Home Key, the Recent Apps Key, the Notifications Key, the Capture+ Key, the QSlide Key, and the Dual window Key.
Tap Color to set the key color. Choose from White and Black.
Tap Hide Home touch buttons to hide the Touch Keys on the apps you select. To access the Touch Key bar from those apps, swipe upward from the bottom of the touchscreen to temporarily redisplay them.