Firstly, it's nice of you to ask these questions for her.

Like ALL new shoes, high heels need to be broken in before wearing them.
The easiest way to do this, I've found, is to put on a thick pair of socks, put the shoes on and wear them around the house. This helps to loosen the upper faster than just putting the shoe on the naked foot. Some shoes take longer to break in than others so she will need to take her time. It might take a few days to get them to the point where they're comfortable enough to wear out of the house.

I'm sure she's the same as any woman and wants to wear the shoes as soon as she buys them... But tell her to be patient. Breaking them in first will save a lot of pain and discomfort in the long run.