navigation_graph.xml

<navigation
   ... >

    <fragment
        android:id="@+id/nav_fragA" 
	... />
        <action
            android:id="@+id/action_navigate_to_fragmentB"
            app:destination="@id/nav_fragB">
        </action>
    </fragment>

    <fragment
        android:id="@+id/nav_fragB"
        … >
        <argument
            android:name="username"
            app:argType="string" />
        <argument
            android:name="password"
            app:argType="string" />
    </fragment>
</navigation>