"Washington New Americans" and "OneAmerica" have free resources on becoming a citizen on their webpage at http://www.wanewamericans.org/oneamerica under the "Become a Citizen" tab.
if you believe your friend to be at all complicated, you should consult with an immigration attorney. I know of a few in Seattle who will do a one-hour consultation for $150. It would be worth it to have the application checked by an expert before submitting it.
Good luck and my future congrats to your friend!
First of all, she need to file for an adjustment of status if she entered the US legally. If she did not enter legally, she will have a different problem. Immigration is very tricky, if you do not know how the system works, you should get an immigration to help in the matter. A single mistake sometimes can cost a lot more than spending some money with an attorney. Our firm has handled hundreds of marriage petitions. I have attached one article regarding marriage : Love Marriage and the Green Card!
Please read it.
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