Tkinter focus...

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import tkinter as tk

root = tk.Tk()

entry = tk.Entry(root)
entry.place(x = '12', y = '50')

#  O segredo tá aqui no Justify
entry.configure(justify = 'right', relief = 'ridge',
        font = ("Serif", 14), fg = '#808080')

button = tk.Button(root, width = '5', height = '1', text = 'ok')
button.place(x = '185', y = '85')
button.configure(font = ("Serif", 10), fg = '#808080')

root.title('Tkinter - Focus')
root.resizable(False, False)
root.config(background = 'white')
root.geometry('250x200')
root.eval('tk::PlaceWindow . center')
root.mainloop()