Injecting a (dynamic library) into an file allows you to add custom features or tweaks to an iOS application, even on non-jailbroken devices. This process typically involves modifying the app's binary to include a load command for the new library and then resigning the package for installation.
If the manual process seems daunting, is a powerful CLI tool that automates the entire workflow. It can inject dylibs, frameworks, and resources into an IPA with a single command:
If everything works, your dylib will be loaded when the app launches.
Guide: Injecting Dylibs into iOS IPA Files for Jailed Devices