Deploy Flutter web app to Firebase Hosting

Step 1: Create a project on Firebase console
Step 2: Download Firebase CLI from here  Firebase CLI binary for Windows.
Step 3: Login via CLI, execute the command firebase login

Step 4: Choose Firebase “Hosting” for Flutter web app when asked for a feature

Step 5: Then, Select an existing Project

Step 6: Choose build/web as a directory & configure as a single-page app

If you see, File build/web/index.html already exists. Overwrite?
Then select NO. So it will not generate a default index.html file

Step 7: Deploy Flutter web to Firebase!

firebase deploy