As baconbutty said, you'll need to use the methods within the user32 library. But, I would also guess that this is a bit advanced for you, though a little help in google can do it.
You'd have to first find the handle for the window, then use SendKeys to send the text to it. It can be done, but you'll have to do some research (google). Since I don't know straight off the top of my head how to do that, and since doing the research won't help me in anyway, it's up to you to do it.
Look at the list here:
API calls list (USER32.DLL)[
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