Get here your google api here https://cloud.google.com/ make sure you have all these apis enabled
Directions API
Geocoding API
Maps SDK for iOS
Maps SDK for ANDROID
Places API
Distance Matrix API
Routes API
in .env put your google maps api key here
GOOGLE_MAPS_API_KEY=GOOGLE_MAPS_API_KEY
and in your ios/Runner/AppDelegate.swift
put your google maps api here
GMSServices.provideAPIKey("GOOGLE_MAPS_API_KEY")
same as android/app/src/main/AndroidManifest.xml
<meta-data android:name="com.google.android.geo.API_KEY" android:value="GOOGLE_MAPS_API_KEY"/>