How Can I Install Apps On My IPhone Without App Store?
Maybe the simplest way to add apps to your iPhone without using the App Store is by using a technique called sideloading. Sideloading is the name used for installing apps directly on the iPhone rather than using the App Store.
Can you download an app that's not on the App Store?
Two ways to download an app that's not on the App Store: From a friend who has it, or a backup. Both require an older version of iTunes. Friend's device: Go to the folder with the app. Copy it to the cloud or removable storage media.
How to Install Apps That Are Missing from the App Store - Lifewire