1. StatelessWidget

1. Immutable: Once created, a StatelessWidget cannot change its properties or behavior.

2. No internal state: Stateless widgets don't have any mutable state. They rely only on the information provided in their constructor and can't change during the widget's lifetime.

3. Lightweight: Since they don’t hold any mutable state, they are lightweight and simple to use.

4. Example use cases: Displaying static content like text, icons, or containers that don't need to change dynamically.

                 import 'package:flutter/material.dart';

                  class MyStatelessWidget extends StatelessWidget {
                    @override
                    Widget build(BuildContext context) {
                      return Container(
                        child: Text('This is a Stateless Widget'),
                      );
                    }
                  }


                  

2. StatefulWidget

1. Mutable state: StatefulWidget can hold mutable state that can change during the lifetime of the widget.

2. State management: These widgets are associated with a separate State object that can change over time in response to various factors like user actions, data changes, etc.

3. Dynamic updates: Ideal for UI components that need to update their appearance or behavior dynamically, such as handling user input, animations, etc.

                  import 'package:flutter/material.dart';

                  class MyStatefulWidget extends StatefulWidget {
                    @override
                    _MyStatefulWidgetState createState() => _MyStatefulWidgetState();
                  }

                  class _MyStatefulWidgetState extends State<MyStatefulWidget> {
                    int _counter = 0;

                    void _incrementCounter() {
                      setState(() {
                        _counter++;
                      });
                    }

                    @override
                    Widget build(BuildContext context) {
                      return Container(
                        child: Column(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: <Widget>[
                            Text('Counter: $_counter'),
                            ElevatedButton(
                              onPressed: _incrementCounter,
                              child: Text('Increment'),
                            ),
                          ],
                        ),
                      );
                    }
                  }

If the widget doesn't require changes in its state, you can use a StatelessWidget. If the widget needs to manage and update its state, then a StatefulWidget is the appropriate choice.