iOS Installation
Before using FlutterFire on iOS, you must first connect to your Firebase project with your iOS application.
Generating a Firebase project configuration file
On the Firebase Console, add a new iOS app or select an
existing iOS app for your Firebase project. The "iOS bundle ID" must match your local project bundle ID. The bundle ID
can be found within the "General" tab when opening ios/Runner.xcworkspace
with Xcode.
Download the GoogleService-Info.plist
file for the Firebase app.
Installing your Firebase configuration file
Next you must add the file to the project using Xcode (adding manually via the filesystem won't link the file to the
project). Using Xcode, open the project's ios/{projectName}.xcworkspace
file. Right click Runner
from the left-hand
side project navigation within Xcode and select "Add files", as seen below:

Select the GoogleService-Info.plist
file you downloaded, and ensure the "Copy items if needed" checkbox is enabled:

Initializing FlutterFire
Once complete follow the instructions on Initializing FlutterFire.
iOS Supported Versions
FlutterFire supports an iOS deployment target of 10 or higher, in line with the requirements of the underlying firebase-ios-sdk.