If you have not created a project for android app on firebase, follow this link to create one and than come back here.
- Go to https://console.firebase.google.com
- click on the existing project where you want to add the IOS app
- click on Add another App link
- select IOS
- enter your package name(you must have got this in email from us) in bundle id field and give a name for your reference eg. XYZ IOS App in App nickname, leave app store id field blank
- Click on Download GoogleService-Info.plist file and click on continue button
- Again click on Continue in the next screen
- And click on Finish in next screen (both 7 and 8 are done by us for you :))
- Open GoogleService-Info.plist file and copy GOOGLE_APP_ID field value, it will look something like this 1:934357332944:ios:8cdf192452ea68f9
- paste this in the Google App Id for IOS in AndroApp->Account Settings tab.