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.