navManifest.xml

 <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme"
      tools:ignore="GoogleAppIndexingWarning">
      <activity android:name=".MainActivity">
          <intent-filter>
              <action android:name="android.intent.action.MAIN" />
              <category android:name="android.intent.category.DEFAULT" />
              <category android:name="android.intent.category.LAUNCHER" />
          </intent-filter>
          <!-- Be sure to include this line for implicit URL Deep Link -->
          <nav-graph android:value="@navigation/nav_item"/>
      </activity>
  </application>