Cemu is a highly popular open-source Wii U emulator originally developed for Windows, later ported to Linux and macOS. An "IPA" file is the format used for iOS applications.
The "Cemu IPA" refers to a specific port of Cemu made by developer OatmealDome. It utilizes MoltenVK (a translation layer that converts Vulkan graphics API calls to Apple's Metal) to run on iPhone and iPad.
Services like Moonlight (paired with Sunshine on your PC) or Steam Link allow you to stream Cemu from your gaming PC to your iPhone. cemu ipa
This is the most critical part of the review. You cannot easily download a pre-made Cemu IPA.
.rpx or .wud/.wux) via file sharing.⚠️ Performance will be poor on all but the newest iPhones (A15+), and many games won’t run or will crash. Cemu is a highly popular open-source Wii U
Regardless of whether you find a Cemu IPA, downloading Wii U games (ROMs) you do not own is illegal in most jurisdictions. To legally emulate, you must dump your own Wii U console's:
Cemu requires a keys.txt file. Do not ask for keys or ROM links; they violate copyright law and subreddit rules. Enable JIT (required for decent speed) using JITStreamer
If you just want to emulate older Nintendo consoles on iOS, use Delta (NES–N64) or Folium (3DS). Wii U emulation on a phone is not practical today.
It sounds like you are looking for information on Cemu, the popular Wii U emulator, specifically regarding iOS (.ipa installation).
Because Cemu is originally written for Windows/Linux (x86 architecture) and iOS devices run on ARM architecture, the situation regarding a .ipa file is unique.
Here is a helpful breakdown of the current state of Cemu on iOS, how it works, and what you need to know.