Student accounts continue to exist in our system after they have been deleted from a teacher's class. How they join a new class depends on how you wish to set up the class this year. You can use a class code, or import from Google or Clever.
If you import from Google Classroom, CommonLit will recognize the student's account from last year and pull that student into your class.
If you sign up your students with a class code, have your student sign into their old account by clicking Log In With Google. Then have them go to My Account and click "Add another class code" and enter your class code for this year.