Listing Installed Apps

When targeting apps that are installed on the device, you'll first have to figure out the correct bundle identifier of the application you want to analyze. You can use frida-ps -Uai to get all apps (-a) currently installed (-i) on the connected USB device (-U):

$ frida-ps -Uai
 PID  Name                 Identifier
----  -------------------  -----------------------------------------
6847  Calendar             com.apple.mobilecal
6815  Mail                 com.apple.mobilemail
   -  App Store            com.apple.AppStore
   -  Apple Store          com.apple.store.Jolly
   -  Calculator           com.apple.calculator
   -  Camera               com.apple.camera
   -  iGoat-Swift          OWASP.iGoat-Swift

It also shows which of them are currently running. Take a note of the "Identifier" (bundle identifier) and the PID if any as you'll need them afterwards.

You can also directly open Grapefruit and after selecting your iOS device you'll get the list of installed apps.