Cydia
Cydia is an alternative app store that allows you to install third-party apps and tweaks on iPhones, iPads, and iPod touches. If you are an iDevice user for a considerable time, you may have already noticed that the Apple app store doesn't offer you third-party apps to install on your device. Therefore, you have to use an alternative app store on your device to get third-party apps and tweaks on the device. And that alternative app store is indeed the Cydia app store because it provides the best-featured third-party apps, extensions, tweaks, add-ons, games, and themes for iDevices.
TrollStore
TrollStore is a utility which is able to permanently sign and install any
application with almost any entitlement with the help of a CoreTrust bug. The latest
releases of TrollStore (specifically 2.0 and later) work through the use of a
CoreTrust bug in which code signatures are not correctly verified under certain
circumstances.
Installing TrollStore is
a process which varies depending on what device and iOS you are running, as a
result, different guides are attached below depending on said combination