start_another_app_pass_data.java

final String key1 = "EMAIL";
final String key2 = "ACCESS_TOKEN";

mSomeButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = getPackageManager().getLaunchIntentForPackage("com.abc.secondapp");
                if(intent != null) {
                    Bundle extras = new Bundle();
                    extras.putString(key1, "SomeEmail@gmail.com");
                    extras.putString(key2, "ldkjgkjgioerjijbmgjQ2349487598");
                    intent.putExtras(extras);
                    startActivity(intent);
                }
            }
        });
        
        
//2nd app, whose package name = "com.abc.secondapp"
@Override
protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main_abcdef);

        String info = "Received Information";

        if (getIntent().hasExtra(key1))
            info = key1 + ":" + getIntent().getStringExtra(key1);

        if (getIntent().hasExtra(key2))
            info = info + "\n" + key2 + ":" + getIntent().getStringExtra(key2);

        TextView resultView = (TextView) findViewById(R.id.received_info);
        if (resultView != null)
            resultView.setText(info);
}