Wat to do is having vagina itch and burn been sexual active since her teens never been to og/gyn and it been 6-7 week since missed period?

Lots of questions: There are a lot of questions here. Foremost is the fact it's been 6-7 weeks since last period, which obviously raises the concern for pregnancy. You need a pregnancy test today or tomorrow. Whether she uses a home test or goes to doc doesn't matter - needs a test urgently, as this makes a difference how urgently the other problems you describe need to be dealt with. Needs STD tests, good exam!