Answers for "how to make a textbox in which you can write android studio"

android studio textbox change text

XML:
<TextView
        android:id="@+id/helloTxt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
        
Java:
TextView msg = findViewById(R.id.helloTxt);
msg.setText("Hello");

Android studio creating a text file

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