Please see the screen shots below, in sequence; to know how you can ensure that your Android apps are always updated.
1) Please tap the Play Store icon in your cell phone.
2) In Play Store, please tap the Hamburger menu [ the top-left 3 horizontal lines ].
3) In the menu, please tap on Settings.
4) In the Settings screen you can see the Auto-update setting.
5) Please tap on the Auto-update area to see the other possible options.
As usual, this is no rocket science! Happy tweaking!