Enter your Apple ID credentials to sign and sideload the app. If you have two-factor authentication, generate an app-specific password on Apple's website.

This is the most reliable "official" method for installing the Electra IPA.

The Electra jailbreak supports a wide range of hardware, including:

iOS 11.2 up to iOS 11.3.1 are fully supported, with limited support for iOS 11.4 beta 1 through 3 on select devices. How to Download and Install Electra 11.3.1