I know it is difficult to accept such unexpected things. And,  your daughter is old enough to make decisions. If she is keeping in touch with you all,  at least as a Mother,  it gives you some hope. Let's her face the world and understand by herself. If it is not manageable,  she will definitely come back. If possible,  guide her to meet a psychologist,  so that she can share her feelings and have some clarity about her future and her decisions.

Hi. From what you have mentioned, it seems that your daughter has some conflicts with you or someone in the family. The best way forward will be to talk to her and ask her as to why she has taken such a step. She is old enough to take her decisions and rather than trying to tell her that she is at fault, one can ask her what she finds wrong in others. However, until and unless your daughter agrees to talk, it will difficult to do anything more.