For GitHub storage, can we use it to upload flows as we do with cloud? In the documentation, it asks for 'path' which is location of an already existing flow file. If yes, how can we do that?

Prefect won't commit your code. You have to commit your flow code first, and then you can reference it in your Storage configuration

ok, so it won't go ahead and store flows like this?

Yeah this will not be pushed to Git. Only the bucket type storages like S3, Azure Blog, and GCS upload for you