By default, TextField doesn’t have any border or style around it so if you don’t have prompt it almost blend itself into the background of the app as you can see below:
We can’t tell if there is any TextField there on screen until user taps on the field. We need to style our TextField better so it can be visible.
There is a modifier to make TextField standout and it’s called TextFieldStyle.
TextFieldStyle has three predefined values: automatic, plain, and roundedBorder.
automatic and plain render TextField without any border whereas roundedBorder style renders a border around TextField. Example below shows the visual difference between them: