Now that you’ve seen the most basic Flutter app, the next section shows how to
take advantage of Flutter’s rich widget libraries to create a modern, polished
app.

How do I use widgets and nest them to form a widget tree?

In Flutter, almost everything is a widget.

Widgets are the basic building blocks of an app’s user interface.
You compose widgets into a hierarchy, called a widget tree.
Each widget nests inside a parent widget
and inherits properties from its parent.
Even the application object itself is a widget.
There is no separate “application” object.
Instead, the root widget serves this role.

A widget can define:

A structural element—like a button or menu

A stylistic element—like a font or color scheme

An aspect of layout—like padding or alignment