Step 1

Open Terminal & navigate to your project directory.

Step 2

Add dependencies by running following command.

flutter pub add flutter_email_sender
flutter pub add url_launcher

Step 3

You can add following code snippet
It could be anywhere.
Ideally, you can put it on a button-press event.
If you are putting it inside a method, make sure you mark the function as async

final Email email = Email(
  body: 'I want to send email and This is where I add email body',
  subject: 'Email subject goes here',
  recipients: ['some-email@gmail.com'],
  isHTML: false,
);
try {
  // this will open native email composer
  await FlutterEmailSender.send(email);
} catch (e) {
  // upon failure (if no email configured)
  // we'll try to launch email composer with URL scheme
  var data = Uri.encodeFull(
      "subject=Email subject goes here&body=I want to send email and This is where I add email body");
  var url =
      Uri.parse('mailto:some-email@gmail.com?$data');
  launchUrl(url);
  log('Something went wrong ${e.toString()}');
}

For Android, you may have to add following lines in AndroidManifest.xml file.

<manifest package="com.mycompany.myapp">
  <queries>
    <intent>
      <action android:name="android.intent.action.SENDTO" />
      <data android:scheme="mailto" />
    </intent>
  </queries>
</manifest>