Answers for "how to add title bar in android studio"

android studio change title bar text

getSupportActionBar().setTitle("Hello world App");

how to remove title bar android studio

change
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
to
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

android studio change menu title

//android studio inside activity java
 getSupportActionBar().setTitle("Your Title");