There are two main flows of getting login credentials for students. It's free registration flow and account creation flow. Member App does not store student or user credentials, so there's no way to know student's password after it's been set.
When a student registers for a new account, they will be asked to provide a new password along with their name and email. For more information on pricing see this article.
After clicking 'Complete Registration' they receive a confirmation email. This email will contain the password they have previously set.
Creating a student account for a paid course
Students can only get access to a paid course by purchasing it or when a user creates an account for them manually. After filling all student details and clicking 'Add', an email will be sent to the student.
This email contains a link to a temporary page where the student can set a password for their account.
The student will be asked to input a new password and confirm it.
Nobody else will know this password and the user is free to choose any password they like. Membership owner will only be able reset student's password, but there's no way to see what password's been set by the student.
After clicking submit new user password will be set and the student will be redirected to their Student Dashboard.