To manually update installed Apps, open the Apple App Store App.
Assuming that you are signed-in to the App Store with your AppleID, at the top-right corner of the App Store Window you will see your initials…
Tap your initials to open the Account Window. Wait for a few seconds for the window to fully load - then perform a downward swipe (within the window) with your finger. If any installed Apps have an available update, the Account Window should list the Apps with a associated Update button; at the top of the list will be an Update All button.