from tkinter import *
from tkinter import messagebox
from tkinter import simpledialog
  
window = Tk()
 
window.title("Το πρώτο μου πρόγραμμα Python σε Windows")
 
window.geometry('600x400')
 
lbl = Label(window, text="Hello")
lbl.place(relx=0.5, rely=0.5, relwidth=0.2, anchor="center") 

 
txt = Entry(window,width=30, fg="blue",  bg="yellow" )
txt.place(relx=0.5, rely=0.7, relwidth=0.2, anchor="center")

l1=Label(window,text="Καλημέρα σας!")
l1.grid(column=1)
 
def clicked():
 
    lbl.configure(text="Button was clicked !!")
    info = messagebox.showinfo('Click Button', 'Button was clicked', parent=window) 

btn = Button(window, text="Click Me", command=clicked, bg="gray50", fg="white", relief=RAISED)
btn.place(relx=0.5, rely=0.8, anchor="center", relwidth=0.4, relheight=0.1)
  
window.mainloop()