You need to enable referral tracking first
The referral tracking is turned off by default. To enable it, click on Manage --> Business Settings --> Referrals and set it to Yes.
What is the referral tracking system and how does it work?
Once the referral system is enabled, every user in Check Cherry will be given a unique referral code that they can use which will display the referring user's name when someone refers a client to your business. Go to Manage --> User Accounts and search for the user's name to find their unique referral code.
When a user shares that url with someone else, and a booking is created from that url, the referring partner will be shown on the booking's overview page.
Video: Client Referral Tracking