-For create a GUI application, we firstly need a window screen at which we can add our widget.
program-
from tkinter import *
win=Tk()
win.mainloop()
output-
-In this program, firstly we import everything from the tkinter module by from tkinter import *, Then we create a window by calling the constructor by Tk() and make object of the window named as 'win' which deals with the every operation on the window screen.
-Here win.mailoop() are used to hold the Screen, we need to write this line in every Tkinter program otherwise output screen is not display.
Change The Title , geometry and background-color of the window screen-
program-
from tkinter import *
win=Tk()
win.title("My first page")
win.geometry("700x400")
win.config(bg="red")
win.mainloop()
output-
-In this program, win.title() change the title of the window screen which shows at the top-left of the window screen.
-win.geometry("700x400") changes the size of the window screen where x=700 and y=400.
-Here 'bg' is used to change the back-ground of the window screen.