You can record a referral against a booking when it is entered by an operator. Please see the Referrals article that details how to do this Referral.
You are able to set up a link which your referral can put on their website, When a customer makes a booking request via this link the referrer will be recorded against the booking. If you are interested in having this available, you will need to get in touch with RCM Support (support@rentalcarmanager.com) and they will walk you through the process.
All commissions given to a referrer are reflected in the Referrals Commission Report generated from Rental Car Manager - Referrals Commission Report
These commissions are often based on the percentage of the booking fees that the referred customer pays to you. Depending on your agreement with your referral partners, you can also provide discounts to referred customers.
There is also a report which will list any bookings made using the referral links you have setup - Referrals Booking Report