Tap on the Apps tab at the top of the screen.
Tap on Store at the top right, then tap on the Menu icon at the bottom of your screen. The Menu icon features three horizontal lines inside a box.
Tap on App Updates displayed at the bottom of your screen. A list of all apps requiring updates will display on-screen.
Tap on Update to the right of each app want updated. Your Kindle will take a few moments to update all the apps you selected.