There are no Amplify specific requirements or setup instructions when targeting web. You will need to use a browser supported by Flutter. See the following Flutter docs for more info:

- [Supported deployment platforms](https://docs.flutter.dev/reference/supported-platforms)
- [FAQ: Which web browsers are supported by Flutter?](https://docs.flutter.dev/development/platform-integration/web/faq#which-web-browsers-are-supported-by-flutter)