The Krisp Referral program is designed to give you the tools to share Krisp with more of your friends so more people will know and use Krisp for free through desktop and chrome extension
You can extend your free usage period of Krisp Pro by inviting your friends to Krisp. You can invite an unlimited number of people and each time someone accepts your invitation, installs Krisp desktop app or Krisp Chrome extension and signs up with an account that didn't exist before, you both will get trial extension.
For each accepted invitation, you get additional 2 months of trial extension and your referral gets additional 1 month.
To get the free months, your account should be on the free plan at the moment of the invitation being accepted.
In case you are on a paid plan at that moment, you won't get any free months from that referral, but they will get one month of free Pro.
For instructions on how to participate in Krisp referral program check this article.