She needs a Visa which can only be obtained though a flight school which is approved by the immigration authorities.
Therefore step one is to choose a flight school. Which one to choose? Well do a search on this site and see what comes up. Alternatively go to Smiths and get Pilot magazine which has a load of adverts and this month also has a "where to fly" guide.
Your friend will also have to go through the TSA security vetting process including having her fingerprints taken. This is not cheap.
However a flight school will give you all the information you need.
If any school tells you either that you dont need a visa and or need to go through the TSA process then they are lying to you. If they will lie on that assume everything else they say is a lie too.