Is the ViewModel responsible for handling all the data related operations of an/a Activity/Fragment?

I recently started learning Android Architecture Components (LiveData, ViewModel and Navigation). So I created a bottom navigation application.

I am putting some sample code here just to talk about as an example.

SampleViewModel class:-

public class DashboardViewModel extends ViewModel {

    private MutableLiveData<String> mText;

    public DashboardViewModel() {
        mText = new MutableLiveData<>();
        mText.setValue("This is dashboard fragment");
    }

    public LiveData<String> getText() {
        return mText;
    }
}

SampleFragmentClass:-

public class DashboardFragment extends Fragment {

    private DashboardViewModel dashboardViewModel;

    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        dashboardViewModel = ViewModelProviders.of(this).get(DashboardViewModel.class);
        View root = inflater.inflate(R.layout.fragment_dashboard, container, false);
        final TextView textView = root.findViewById(R.id.text_dashboard);
        dashboardViewModel.getText().observe(this, new Observer<String>() {
            @Override
            public void onChanged(@Nullable String s) {
                textView.setText(s);
            }
        });
        return root;
    }
}

Let me be clear that there nothing wrong with these pieces of code.

I just want to ask some questions: -

1. Is the ViewModel fully responsible for loading the data that will be used by an activity or a fragment?

2. If I need to get some data from the server, would I call the API from ViewModel or the activity itself?

3. If I need to do some context-based actions, I would do that in the activity or a fragment. Is there some convention or guideline that I should do it in the ViewModel?