If your device is running a compatible iOS version (typically iOS 14.0 - 17.0 depending on the device), TrollStore
Many "free IPA" repositories are run by ad networks. When you sideload their IPA, the code runs a background script that collects your Device ID (UDID), phone number, and Apple ID email. This information is then sold to spammers or used to lock your Apple ID. youtube studio ipa link
(Wait, that's confusing, right?)
If you still want to proceed: