If you still can't find it, try resetting the home screen by selecting “Settings” > “General “> “Reset” > “Reset Home Screen Layout“. This should return your icons to default settings and restore the App Store icon.If app store missing then Go to Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases >click on Installing Apps > Make sure the Allow button is on. If this tip works for you, getting back the iPhone App Store icon.