For Nintendo 3DS emulation on iPhone or iPad, users typically rely on that have been specifically ported to iOS. Current 3DS Emulators for iOS

Once AltStore is on your iPhone:

Before clicking any shady links, let’s understand the technology.

The keyword brings you to the frontier of iOS gaming. It is not a simple App Store tap, but for emulation enthusiasts, the extra steps are the price of freedom on a "walled garden" phone.

Since you cannot just tap an IPA file on iOS, you need AltStore.