There are 2 ways your can use to invite people to your course.

From the "People" page you can find the button "Invite Participants"

Once clicked you will see two options:

Once clicked will be possible to inset name email and eventual discount amount in percentage.

With this option, you can upload a list of students to be uploaded. The required fields are Name, and Email.

It's possible to add also a discount column please set a number from 0 to 100 which represents the percentage.