pack_tk

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
import tkinter as tk
from tkinter import ttk

ventana = tk.Tk()
ventana.title("PACK")

caja = ttk.Entry()
caja.pack()

boton = ttk.Button(text="HOLA")
boton.pack(padx=30, pady=30, ipadx=50, ipady=70)

boton = ttk.Button(text="HOLA MUNDO")
boton.pack(expand=True, fill=tk.BOTH)

etiqueta = ttk.Label(text="JAJAJAJA")
etiqueta.pack(after=caja)

ventana.mainloop()