Have flutter project in hand which is built for Android and iOS, now want to built desktop and web counter part?

Make sure that you have enabled, web, desk features. To ensure this run the following

Flutter devices

If not please go through the web/desk support post.

Here is the solution

Make sure you had an active internet connection.

Cd to your project folder and in the console enter these commands

For few second it will add tools for desktop and web features.

Flutter create . 

Run the flutter command

Flutter run -d chrome

Flutter will goes through building process and will bring you a local host id.

For desk top try to run

Flutter run -d windows/linux/mac