import tkinter as tk

parent = tk.Tk()
# create the widget.  Make sure to save a reference.
mytext = tk.Text(parent)

# insert a string at the beginning
mytext.insert('1.0', "I love my text widget!")

# insert a string into the current text
mytext.insert('1.2', 'REALLY ')

# get the whole string
mytext.get('1.0', tk.END)

# delete the last character.
# Note that there is always a newline character
# at the end of the input, so we backup 2 chars.
mytext.delete('end - 2 chars')

mytext.pack()
parent.mainloop()