Step 1:Add get package to pubspec.yaml file:

                        get: 
                      

Step 2: Import get package in main.dart file

                      import 'package:get/get.dart';
                      

Step 3: Define routes on GetMaterialApp():

					   void main() {
						runApp(
							GetMaterialApp(
							initialRoute: '/',
							unknownRoute: GetPage(name: '/notfound', page: () => UnknownRoutePage()), //like 404 page in web
							getPages: [
								GetPage(name: '/', page: () => MyHomePage()),
								GetPage(name: '/second', page: () => Second()),
								GetPage(
								name: '/third',
								page: () => Third(),
								transition: Transition.zoom  
								),
							],
							)
						);
						}

						

To go to new named route page:

						Get.toNamed("/NextScreen");
						

To go to new page with arguement:

						Get.toNamed("/NextScreen", arguments: 'Get is the best');
						

get argument on next screen:

						print(Get.arguments);
						

Go to new page with dynamic parameters on route names:

						Get.offAllNamed("/NextScreen?device=phone&id=354&name=Enzo");
						

on new screen, get these parameters:

						print(Get.parameters['id']);
						// out: 354
						print(Get.parameters['name']);

					    

Full code

						import 'package:flutter/material.dart';
import 'package:get/get.dart';
void main() {
  runApp(
    GetMaterialApp(
      home: MyApp(),
    )
  );
}

class MyApp extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return Scaffold(
          appBar: AppBar(
              title:Text("Navigation Using GetX"),
              backgroundColor: Colors.purple,
          ),
          body: Container( 
              alignment: Alignment.center,
              child: Column(
                children: [
                    ElevatedButton(
                      onPressed:(){
                          Get.to(PageOne());
                      }, 
                      child: Text("Go to Page One")
                    ),

                    ElevatedButton(
                      onPressed:(){
                          Get.off(PageTwo());
                      }, 
                      child: Text("Go to Page Two and Clear Previous Route")
                    ),

                    ElevatedButton(
                      onPressed:(){
                          Get.offAll(PageThree());
                      }, 
                      child: Text("Go to Page Three and Clear All Previous History")
                    ),
                ],
              ),     
          )
      );
  }
}

//Screen One, you can create another file for this class
class PageOne extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
      return Scaffold(
         appBar: AppBar(title:Text("Page One")),
         body: Container(
           alignment: Alignment.center,
            child: ElevatedButton(
               onPressed:(){
                   Get.back();
                   //go to previous page
               }, 
               child: Text("Go Back")
              ),
         ),
      );
  }

}

//Screen Two, you can create another file for this class
class PageTwo extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return Scaffold(
         appBar: AppBar(title:Text("Page Two")),
         body: Container(
           alignment: Alignment.center,
            child: ElevatedButton(
               onPressed:(){
                   Get.back();
                   //app will be closed, because there is one previous route, and its cleared,
                   //if there were many previous routes, it will escape, one back route, because, 
                   //the route just before this page is cleared by Get.off().
               }, 
               child: Text("Go Back")
              ),
         ),
      );
  }
}

//Screen Three, you can create another file for this class
class PageThree extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
     return Scaffold(
         appBar: AppBar(title:Text("Page Three")),
         body: Container(
            alignment: Alignment.center,
            child: ElevatedButton(
               onPressed:(){
                   Get.back();
                   //app will closed, because all previous route history are cleared
                   // by Get.offAll()
               }, 
               child: Text("Go Back")
              ),
         ),
      );
  }

}

Another example

in main.dart

return GetMaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'GetX Store',
      initialBinding: StoreBinding(),
      theme: Themes.lightTheme,
      darkTheme: Themes.darkTheme,
      themeMode: themeController.theme,
      initialRoute: '/',
      getPages: [
        GetPage(
          name: '/',
          page: () => Home(),
        ),
        GetPage(name: '/edit_name', page: () => UpdateStoreName()),
        GetPage(name: '/add_followers', page: () => AddFollowers()),
        GetPage(name: '/toggle_status', page: () => StoreStatus()),
        GetPage(name: '/edit_follower_count', page: () => AddFollowerCount()),
        GetPage(name: '/add_reviews', page: () => AddReviews()),
        GetPage(name: '/update_menu', page: () => const UpdateMenu()),
      ],
      home: Home(),
    );

  

in call

             onTap: () {
                // closes the drawer and goes to another screen
                Get.offAndToNamed('/edit_name');
                
              }),

    

Here used named route instead of function name