When you invite parents to the class via the Type emails manually option, all the emails you paste in the To field will each get an invitation email individually. They will not see any other emails you entered in the To field.

However, when you invite parents to the class via the Use your phone's email app or Gmail option, the emails you entered in the To field within your email client will be seen by all the parents to which the invitation was sent. It is like any other email with all the email addresses in the To field.

Please note: If you are not comfortable with other parents seeing the email addresses, please use the Type emails manually option.