1) Start the software

from pywinauto.application import Application

app = Application(backend='uia').start('notepad.exe')

2) What is the window?

window = app['Untitled - Notepad']

3) Get all controlers in window

window.print_control_identifiers()

4) Type your text in type_keys area

window..wrapper_object().type_keys("your text",with_spaces=True)