To answer this question, we usually understand that ipa is installed in the App Store, but some applications can be installed by downloading links directly from your browser without going through the App Store. This method is usually nothing more than three methods: legal person signature, super signature and tf signature.

These three signature methods allow ipa files to be installed directly on Apple phones without going through the App Store.

But their principles and installation methods are different, and their stability is also different. See this article for details, and specifically introduce three methods of directly installing ipa files on iPhone. How to install ipa directly on iphone? Enterprise signature, super signature, tf signature

As for whether it will be poisoned, it is necessary to know that corporate signatures and super-signatures do not need Apple's review, so users are advised to determine the source of applications before installation to avoid installing applications containing sensitive content. Tf signature needs to be reviewed by Apple, so the security is guaranteed.