Create a new xml file; res/menu/menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      tools:context=".MainActivity">

    <item
        android:id="@+id/action_add"
        android:icon="@drawable/ic_action_add"
        android:orderInCategory="100"
        android:title="@string/action_search"
        app:showAsAction="ifRoom"/>

    <item
        android:id="@+id/action_search"
        android:icon="@drawable/ic_action_search"
        android:orderInCategory="100"
        android:title="@string/action_search"
        app:showAsAction="ifRoom"/>

    <item
        android:id="@+id/action_settings"
        android:icon="@drawable/ic_action_settings"
        android:orderInCategory="100"
        android:title="@string/action_settings"
        app:showAsAction="ifRoom"/>
</menu>

To add the menu in the activity you need to override following two methods;

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                //Do some action
                return true;
            case R.id.action_settings: {
                //Do some action
                return true;
            }
            case R.id.action_add: {
                //Do some action
                return true;
            }
        }
        return super.onOptionsItemSelected(item);
    }

Fragments will follow the same menu is an in the parent activity. In case you want to modify menu for a fragment, you have to setHasOptionsMenu(true) in onCreate method;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

Now you can manipulate a menu. Let’s say you want to hide a specific action;

@Override
public void onCreateOptionsMenu(Menu menu , MenuInflater inflater){
    mMenu.findItem(R.id.action_add).setVisible(false);
    super.onCreateOptionsMenu(menu,inflater);
}

You can also hide the whole menu for a fragment;

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    menu.clear();
}

You can create a fragment specific menu and inflate the menu for that fragment. Create a new menu i.e. res/menu/menu_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      tools:context=".MainActivity">
    <item
        android:id="@+id/action_settings"
        android:icon="@drawable/ic_action_settings"
        android:orderInCategory="2"
        android:title="@string/action_settings"
        app:showAsAction="ifRoom"/>
</menu>

and now you can either extend this menu with the activity menu or use it as the only menu.

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    //map.clear(); //Clear the previous menu from the activity.
    inflater.inflate(R.menu.menu_fragment, menu);
}

Now you can override the method onOptionsItemSelected to handle item selection.