I can't believe my great Scrabble opponent hasn't got Scrabble on her iPhone!!!
All you do is make sure you have iTunes on your pc/laptop, connect the phone to your pc/laptop with a USB cable, your iphone will show up in iTunes, click on it, then choose 'sync'. There should be an automatic update prompt from iOS 5 to iOS 6, and then any apps you download to your computer in iTunes are automatically transferred to your iPhone.