How to share tts as and audio file in android studio

Question

I'm new to programming, and I'm creating an app with texttospeech and I wanna be able to share the tts output as an audio file to other apps like whatsapp for example. I have heard about synthesizetofile() but I don't know anything about it. Here's my code:

Main Activity class

package com.example.texttospeech;

import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.speech.tts.TextToSpeech;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import androidx.appcompat.app.AppCompatActivity;

import java.io.File;
import java.util.HashMap;
import java.util.Locale;

public class MainActivity extends AppCompatActivity {

     EditText etInput;
     Button btDone, btShare;
     MediaPlayer mMediaPlayer;

     TextToSpeech textToSpeech;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        etInput = findViewById(R.id.et_input);
        btDone = findViewById(R.id.bt_done);
        btShare = findViewById(R.id.btn_share);
        textToSpeech = new TextToSpeech(getApplicationContext()
                , new TextToSpeech.OnInitListener() {
            @Override
            public void onInit(int i) {
                if (i == TextToSpeech.SUCCESS) {
                    int lang = textToSpeech.setLanguage(Locale.ENGLISH);
                }
            }
        });


        btDone.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //String s = etInput.getText().toString();
                //int speech = textToSpeech.speak(s, TextToSpeech.QUEUE_FLUSH, null);

                HashMap<String, String> map = new HashMap<>();
                map.put(TextToSpeech.Engine.KEY_PARAM_UTTERANCE_ID, "speak");

                File myDir = getApplicationContext().getFilesDir();
                String documents = "documents/data";
                File documentsFolder = new File(myDir, documents);
                documentsFolder.mkdir();

                String path = "/"+documents+"/"+"test.mp3";

                textToSpeech.synthesizeToFile("text to speech to audio", map, path);
                mMediaPlayer = new MediaPlayer();
                try{
                    mMediaPlayer.setDataSource(path);
                    mMediaPlayer.prepare();
                }
                catch (Exception e) {
                    Log.d("ROYs", e.toString());
                    e.printStackTrace();
                }
                mMediaPlayer.start();

            }
        });

        btShare.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Bundle bundle = new Bundle();
                Intent intent = new Intent( Intent.ACTION_SEND );
                intent.setType("audio/mp3");
                startActivity( intent );

            }
        });

    }

    private void shareAudio()
    {
       Bundle bundle = new Bundle();
       Intent intent = new Intent( Intent.ACTION_SEND );
       intent.setType("audio/mp3");
       startActivity( intent );
    }
}

Anyone who helps, would be appreciated very much!