how to format and create a word counter

• I do not how to bind my view model to three buttons, to format to bold, italic and underline 
• how do a create a word counter on my VM
• open the richtextbox when creating a new note

        public ICommand ExitCommand { get; set; }
    public ICommand NewNotebookCommand { get; set; }
    public ICommand NewNoteCommand { get; set; }
    public ObservableCollection<Notebook> Notebooks { get; set; }
    public ObservableCollection<Note> Notes { get; set; }
 
    DateTime date = DateTime.Now;
 
    private Notebook _SelectedNoteBook;
    public Notebook SelectedNoteBook {
        get { return _SelectedNoteBook; }
        set {
            if (_SelectedNoteBook != value) {
                _SelectedNoteBook = value;
                RaisePropertyChanged();
                GetNotes();
            }
        }
    }
 
 
    public NotesWindowVM() {
 
        Notes = new ObservableCollection<Note>();
        Notebooks = new ObservableCollection<Notebook>();
 
        ExitCommand = new Command(() => {
            Application.Current.Shutdown();
        });
        NewNotebookCommand = new Command(() => {
            CreateNewNotebook();
        });
        NewNoteCommand = new HelperCommand {
            ExecuteDelegate = x => CreateNewNote(SelectedNoteBook.Id),
            CanExecuteDelegate = x => SelectedNoteBook != null
        };
 
        GetNoteBooks();
    }
 
    private void CreateNewNote(int NotebookId) {
        Note note = new() {
            NotebookId = NotebookId,
            CreatedAt = DateTime.Now,
            UpdatedAt = DateTime.Now,
            Title = $"Created on {DateTime.Now}"
        };
        Database.Insert(note);
 
        GetNotes();
    }
 
    private void CreateNewNotebook() {
        Notebook notebook = new() { Name = "New Notebook" };
        Database.Insert(notebook);
 
        GetNoteBooks();
    }
 
    private void GetNoteBooks() {
 
        var notebooks = Database.Read<Notebook>();
 
        Notebooks.Clear();
        foreach (var item in notebooks) {
            Notebooks.Add(item);
        }
    }
 
    private void GetNotes() {
 
        if (SelectedNoteBook != null) {
            var notes = Database.Read<Note>().Where(
                n => n.NotebookId == SelectedNoteBook.Id)
                .ToList();
 
            Notes.Clear();
            foreach (var item in notes) {
                Notes.Add(item);
            }
        }
    }
}

Any help would be appreciated