How do I transfer Phonegap app to my iPhone
The easiest way is using a Mac.  Xcode (using the Devices window) can install ipa files on developer registered iOS devices.  The Apple Configurator 2 app (available from the Mac App store) will also allow you to select ipa files and install them (assuming they are provisioned correctly) on iOS devices.

Without a Mac, it may be possible to use an https service that allows downloading a correctly provisioned app (Ad Hoc or Enterprise) using a wireless installation manifest.