Row with spacer

main.dart

import 'package:flutter/material.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(
        scaffoldBackgroundColor: darkBlue,
      ),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: MyWidget(),
        ),
      ),
    );
  }
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        SizedBox(
          height: 80,
          child: Row(
            children: [
              const Text('Members'),
              IconButton(
                onPressed: (){},
                icon: const Icon(Icons.warning),
              ),
              const Spacer(),
              TextButton(
                onPressed: (){},
                child: const Text('Invite members'),
              ),
            ],
          ),
        ),
      ],
    );
  }
}