def one_button():
    text_int.insert("1.0", "1")
    return

def two_button():
    text_int.insert("1.0", "2")
    return

text_int = Text(root, width = 30, height = 1, )
text_int.place(x = 63, y = 25)

one_button_f = Button(root, text = "1", command = one_button, width = 12, height = 1)
one_button_f.place(x = 34, y = 80)

two_button_f = Button(root, text = "2", command = two_button, width = 12, height = 1)
two_button_f.place(x = 150, y = 80)