I guess you first have to contact italki. Look at the bottom of your italki Website and apply. Good luck

Hi! Enter to edit profile then change your profile anything you want.if there is spealling mistakes. Good luck

You become a student as soon as you either, buy credits, or take a class (not which one does it). I'm not sure what you should do to become a teacher, but probably here: https://www.italki.com/teacher/apply