Adoption may not be a good option since your friend is over 16. She may consider finding a fiance in the United States or enter the US on non-immigrant visa, such as student visa or employment visa. There are might be other possibilities available to your friend depending on the individual circumstances. US immigration laws are complex and ever-changing. Consult an expereinced immigration lawyer to discuss other available options for your friend. The response and information are intended to be general and should not be relied upon for any specific situation.
Your friend now in India has a number of options, but adoption is not one of them because she is over 16. Perhaps, the quickest and most effective measure would be to return as a student at a junior college, college, or university. Almost all of these institutions have offices that assist foreign students. If she were a good student, she could stay in the U.S. for quite a while. You could be big help. She could also try to return on other temporary, non-immigrant visas, such as a J-1 or H2B visa. Both of these visa have negative aspects or are quota-limited, however. The J-1 covers Au pairs, Camp Counselors, Summer work/travel, and trainees, especially in the hospitality industry. If she happens to meet "Mr. Right" while the U.S., there is an immediate path to a Green Card as the spouse of a citizen. For further information, go to www.uscis.gov and www.travel.state.gov/visa/temp.
I agree that adoption is probably not viable here; but one good thing for your friend is that she is likely not subject to "unlawful presence" restrictions since her time in the US without a visa status was when she was a minor. So probably she should consider US visa options like any other foreign national. If she is 18, then perhaps a student visa is appropriate - and you and your family could serve as 'financial sponsors' to help cover her tuition costs. That might be a great way to help your friend.
Generally the most efficient way to obtain information on student visas is to contact colleges and universities authorization to admit international students and get information on admission requirements. Normally your friend would do some research online to find some college programs he or she may like, then you could help follow-up if the school is local to you. Colleges and universities authorized to admit international students will have an international student office or coordinator who can provide further details.
I suspect your friend, or her family, used an attorney in connection with the voluntary departure case, and so she will want very good documentation of that case if she seeks a student visa or any other kind of US visa.
Immigration Green cards Employment-based green cards US visas Non-immigrant visas Student visas F-1 visa for students International student employment Voluntary departure for deportation Immigrant status Immigrants and education Immigrants and college Employment Education law Foreign and immigrant workers Family law