Fortnite can be reinstalled on iOS, even though Apple has removed it
Apple pulled off Fortnite from the App Store after Epic Games slipped in a new payment method for players in-game to avoid paying Apple the 30% fee it charges for in-app purchases. Google soon followed suit and pulled Fortnite off the Play Store as well.
While Google still allows side-loading apps on Android devices (here’s how you can download Fortnite on Android), Apple has no such workaround. So, if you have not downloaded Fortnite on any of your Apple devices, you are out of luck and will have to wait till this whole legal tussle between Apple and Epic Games gets sorted out.