Online Demo: https://fluttercommunity.github.io/flutter_sms/

Flutter Plugin for sending SMS and MMS on Android and iOS. If you send to more than one person it will send as MMS. On the iOS if the number is an iPhone and iMessage is enabled it will send as an iMessage.

You can send multiple ways:

1. Message and No People
2. People and No Message
3. Message and People

This will populate the correct fields.

Make sure to Install and Import the Package.

import 'package:flutter_sms/flutter_sms.dart';

Create a function for sending messages.

void _sendSMS(String message, List<String> recipents) async {
 String _result = await sendSMS(message: message, recipients: recipents)
        .catchError((onError) {
      print(onError);
    });
print(_result);
}

You can quickly send the message with this function.

String message = "This is a test message!";
List<String> recipents = ["1234567890", "5556787676"];
_sendSMS(message, recipents);

WARNING, there is a narrow category of apps that can get into the play store using this feature. Using it is only advisable if you fit into this category or you intent to distribute through a third party platform

On Android, you can skip the additional dialog with the sendDirect parameter.

String message = "This is a test message!";
List<String> recipents = ["1234567890", "5556787676"];
 String _result = await sendSMS(message: message, recipients: recipents, sendDirect: true)
        .catchError((onError) {
      print(onError);
    });
print(_result);

NOTE: This also requires the SEND_SMS permission to be added to the AndroidManifest.xml

    <uses-permission android:name="android.permission.SEND_SMS"/>
    
    <application
      ...

iOS SMS	Android MMS

You can find other screenshots here.