bu

import tkinter, sys

def koniec():
    sys.exit()

def zmiana():
    l.config(text = "Wcisnij Zakoncz")

main = tkinter.Tk()


l = tkinter.Label(main, text = "Wcisnij przycisk ponizej")
b = tkinter.Button(main, text = "Zakończ", command = koniec)
b2 = tkinter.Button(main, text = "Przycisk", command = zmiana)

l.pack()

b.pack()
b2.pack()
main.mainloop()