Програма:
import tkinter as tk

def file_new():
save_or_not = tk.Tk()
save_or_not.geometry("150x70+400+250")
save_or_not.resizable(False, False)
save_or_not.grid_columnconfigure(0, minsize=75)
save_or_not.grid_columnconfigure(1, minsize=75)
saving_label = tk.Label(save_or_not, text="Save file?")
saving_label.grid(columnspan=2)
def without_saving():
save_or_not.destroy()
global text
text.delete('1.0', tk.END)
def saving():
file_save()
save_or_not.destroy()
global text
text.delete('1.0', tk.END)
yes_button = tk.Button(save_or_not, text="Yes", width=8, command=saving)
no_button = tk.Button(save_or_not, text="No", width=8, command=without_saving)
yes_button.grid(column=0, row=1)
no_button.grid(column=1, row=1)

def file_open():
file_name = filedialog.askopenfilename(initialdir='/',
title='Open file',
filetypes=(('Text Documents', '*.txt'),
('allfiles', '*.*')))
if file_name:
with open(file_name, 'r') as f:
text_open = f.read()
if text_open != tk.NONE:
text.delete(1.0, tk.END)
text.insert(tk.END, text_open)
else:
text.delete(1.0, tk.END)

def file_save():
file_name = filedialog.asksaveasfilename(initialdir='/',
title='Select file',
filetypes=(('Text Documents', '*.txt'), ('allfiles', '*.*')))
if file_name:
with open(file_name + ".txt", 'w') as f:
text_save = str(text.get(1.0, tk.END))
f.write(text_save + '\n')

def file_exit():
root.destroy()

def help_function():
help_window = tk.Tk()
help_window.geometry("300x70+400+250")
help_window.resizable(False, False)
help_label = tk.Label(help_window, text="Link to instructions\nhttps://www.wikihow.com/Use-Notepad")
help_label.pack()
def back():
help_window.destroy()
back_button = tk.Button(help_window, text="Back", command=back, width=10)
back_button.pack()

def about():
about_window = tk.Tk()
about_window.geometry("300x70+400+250")
about_window.resizable(False, False)
help_label = tk.Label(about_window, text="ItStep\nThanks for using!")
help_label.pack()
def back():
about_window.destroy()
back_button = tk.Button(about_window, text="Back", command=back, width=10)
back_button.pack()

def setting():






root = tk.Tk()
root.geometry("600x400+200+100")
root.title("Magician's diary")
root.iconbitmap("Note.ico")
root.minsize(200,100)
root.maxsize(1920,1080)

menu= tk.Menu(root)
root.config(menu=menu)

file_menu = tk.Menu(menu, tearoff=0)
file_menu.add_command(label='New', command=file_new)
file_menu.add_command(label='Open', command=file_open)
file_menu.add_command(label='Save as', command=file_save)
file_menu.add_command(label='Exit', command=file_exit)
menu.add_cascade(label='File', menu=file_menu)


help_menu = tk.Menu(menu, tearoff=0)
help_menu.add_command(label='Help', command= help_function)
help_menu.add_command(label='About', command=about)
menu.add_cascade(label='Help', menu=help_menu)




root.mainloop()

import tkinter as tk

from tkinter import filedialog

from tkinter import ttk

def file_new():

   save_or_not = tk.Toplevel(root)

   save_or_not.geometry("150x70+400+250")

   save_or_not.resizable(False, False)

   save_or_not.grid_columnconfigure(0, minsize=75)

   save_or_not.grid_columnconfigure(1, minsize=75)

   saving_label = tk.Label(save_or_not, text="Save file?")

   saving_label.grid(columnspan=2)

   def without_saving():

       save_or_not.destroy()

       text.delete('1.0', tk.END)

   def saving():

       file_save()

       save_or_not.destroy()

       text.delete('1.0', tk.END)

   yes_button = tk.Button(save_or_not, text="Yes", width=8, command=saving)

   no_button = tk.Button(save_or_not, text="No", width=8, command=without_saving)

   yes_button.grid(column=0, row=1)

   no_button.grid(column=1, row=1)

def file_open():

   file_name = filedialog.askopenfilename(initialdir='/', title='Open file', filetypes=(('Text Documents', '*.txt'), ('all files', '*.*')))

   if file_name:

       with open(file_name, 'r') as f:

           text_open = f.read()

           if text_open != tk.NONE:

               text.delete(1.0, tk.END)

               text.insert(tk.END, text_open)

           else:

               text.delete(1.0, tk.END)

def file_save():

   file_name = filedialog.asksaveasfilename(initialdir='/', title='Select file', filetypes=(('Text Documents', '*.txt'), ('all files', '*.*')))

   if file_name:

       with open(file_name + ".txt", 'w') as f:

           text_save = str(text.get(1.0, tk.END))

           f.write(text_save + '\n')

def file_exit():

   root.destroy()

def help_function():

   help_window = tk.Toplevel(root)

   help_window.geometry("300x70+400+250")

   help_window.resizable(False, False)

   help_label = tk.Label(help_window, text="Link to instructions\nhttps://www.wikihow.com/Use-Notepad")

   help_label.pack()

   def back():

       help_window.destroy()

   back_button = tk.Button(help_window, text="Back", command=back, width=10)

   back_button.pack()

def about():

   about_window = tk.Toplevel(root)

   about_window.geometry("300x70+400+250")

   about_window.resizable(False, False)

   help_label = tk.Label(about_window, text="ItStep\nThanks for using!")

   help_label.pack()

   def back():

       about_window.destroy()

   back_button = tk.Button(about_window, text="Back", command=back, width=10)

   back_button.pack()

def open_settings():

   def apply_settings():

       font = font_combobox.get()

       size = size_combobox.get()

       style = style_combobox.get()

       text.config(font=(font, size, style))

       settings_window.destroy()

   settings_window = tk.Toplevel(root)

   settings_window.geometry("300x200+400+250")

   settings_window.resizable(False, False)

   font_label = tk.Label(settings_window, text="Font:")

   font_label.pack()

   font_combobox = ttk.Combobox(settings_window, values=["Calibri", "Arial", "Comic Sans MS", "Tahoma", "Verdana"])

   font_combobox.pack()

   size_label = tk.Label(settings_window, text="Size:")

   size_label.pack()

   size_combobox = ttk.Combobox(settings_window, values=["8", "10", "12", "14", "16"])

   size_combobox.pack()

   style_label = tk.Label(settings_window, text="Style:")

   style_label.pack()

   style_combobox = ttk.Combobox(settings_window, values=["normal", "bold", "italic"])

   style_combobox.pack()

   apply_button = tk.Button(settings_window, text="Apply", command=apply_settings)

   apply_button.pack()

root = tk.Tk()

root.geometry("600x400+200+100")

root.title("Magician's diary")

# root.iconbitmap("Note.ico")  # Поміняйте на шлях до власного файлу значка

root.minsize(200, 100)

root.maxsize(1920, 1080)

menu = tk.Menu(root)

root.config(menu=menu)

file_menu = tk.Menu(menu, tearoff=0)

file_menu.add_command(label='New', command=file_new)

file_menu.add_command(label='Open', command=file_open)

file_menu.add_command(label='Save as', command=file_save)

file_menu.add_command(label='Exit', command=file_exit)

menu.add_cascade(label='File', menu=file_menu)

settings_menu = tk.Menu(menu, tearoff=0)

settings_menu.add_command(label='Font Settings', command=open_settings)

menu.add_cascade(label='Settings', menu=settings_menu)

help_menu = tk.Menu(menu, tearoff=0)

help_menu.add_command(label='Help', command=help_function)

help_menu.add_command(label='About', command=about)

menu.add_cascade(label='Help', menu=help_menu)

text = tk.Text(root)

text.pack(fill=tk.BOTH, expand=True)

root.mainloop()

Будь ласка, постав найкращу відповідь