Help Navigation Drawer Android Studio

In your layout of the "item" add another TextView where you can add the text "Premieres", this is an example:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="48dp"
    android:background="@android:color/holo_green_dark">

    <ImageView
        android:id="@+id/icon"
        android:layout_width="25dp"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_marginLeft="12dp"
        android:layout_marginRight="12dp"
        android:contentDescription="@null"
        android:src="@drawable/ic_subway"
        android:layout_centerVertical="true" />

    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_toRightOf="@id/icon"
        android:text = "Seccion"
        android:textColor="@android:color/white"
        android:gravity="center_vertical"
        android:paddingRight="40dp"/>

    <TextView android:id="@+id/category"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"
        android:text = "Estrenos"
        android:layout_marginRight="8dp"
        android:textColor="@android:color/white"/>

</RelativeLayout>

@NicolasSchmidt, I recommend you see the example of this link: link that I posted in another answer, you can configure your view, in this case add the TextView so that the text "Premieres" appears, see drawer_list_item.xml .

What I can think of is that you create a new layout with the textview i.e texto_estreno.xml:

 <?xml version="1.0" encoding="utf-8"?>
 <TextView 
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:gravity="center_vertical"
    android:text="Estrenos"/>

Afterwards in your DrawerMenu item you can refer to the layout where the Textview is, i.e:

<item  app:actionLayout="@layout/texto_estreno"   />

That way you can customize the layout where the text is "Releases "to your liking, colors, styles, font type, etc.

UPDATE

Another way that is not the best is to do it with SpannableString :

I'm not sure about the number of the characters, it's a matter of placing the corresponding number:

NavigationView navigation = (NavigationView)findViewById(R.id.navigation);
Menu menuNav = navigation.getMenu();
MenuItem element = menuNav.findItem(R.id.item5); //Aquí colocas tu item
String before = element.getTitle().toString();

String texto = "Estrenos";
String s = before + "   "+texto+" ";
SpannableString sColored = new SpannableString( s );

sColored.setSpan(new BackgroundColorSpan( Color.GRAY ),3, 3,  0);

sColored.setSpan(new ForegroundColorSpan( Color.WHITE ), 3, 3,0);


element.setTitle(sColored);